Solid Electrolytic Capacitor Packaging With Capillary-Filled Substrates

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Solution Overview

Problem

The packaging of solid electrolytic capacitors faces challenges in achieving low profile and high reliability due to the small anode area, which complicates electrical connections and mechanical strength, especially when multiple elements are stacked, and conventional molding processes can damage the capacitor elements or electrodes during thin packaging.

Innovation Solution

A new packaging structure using two protective substrates with anodic and cathodic conductor pads to sandwich capacitor elements, filled with an insulating material, and a capillary filling process to minimize stress, with subsequent metal depositions to form external terminals, enhancing mechanical strength and adhesion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional molding processes are used to package capacitor elements, then the packaging can be completed, but the capacitor elements or electrodes may be damaged during the process

Engineering Contradiction:

Improveintegrity of capacitor elementsVSAvoidpackaging process complexity

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies preliminary action by pre-attaching conductor pads to the capacitor elements before the molding process. This preparation ensures that the elements are securely positioned and electrically connected before undergoing the stressful molding operation, preventing damage during packaging

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent implements beforehand cushioning by using a support structure during molding that distributes and reduces viscous stress on the capacitor elements. This cushioning effect protects the elements from damage while still allowing the molding process to proceed

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Volume of moving object

If the package envelope is made as close to the capacitor element as possible to minimize footprint, then the profile is reduced, but the mechanical strength and connection reliability deteriorate

Engineering Contradiction:

Improvepackage footprintVSAvoidmechanical strength of package

Core Design Contradiction:

Volume of moving objectVSStrength

Solution Approach 1:

The patent applies local quality by concentrating structural reinforcement and conductor pad attachment at specific critical locations on the capacitor element, rather than uniformly increasing package size. This allows minimal overall footprint while providing localized strength where needed for connections and support

Inventive Principle:

Principle #3Local quality

3Quantity of substance

If the anode area is made small to maximize dielectric interface area, then the capacitance is improved, but the electrical connection and mechanical strength become difficult to maintain

Engineering Contradiction:

ImprovecapacitanceVSAvoidelectrical connection reliability

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent applies dimensionality change by extending the conductor pad in the vertical dimension (thickness direction) to compensate for the reduced horizontal anode area. This vertical extension provides sufficient surface area for reliable electrical connection and mechanical attachment without increasing the footprint, thereby maintaining capacitance while ensuring connection reliability

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 allows for efficient, reliable, and cost-effective packaging of solid electrolytic capacitors with reduced equivalent series resistance (ESR) and improved mechanical strength, addressing the challenges of small anode areas and conventional molding limitations.

Implementation Method 1

a capillary filling process to minimize stress

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 2

subsequent metal depositions to form external terminals

Methodology Applied

Scientific EffectMetal deposition: Deposition (physical)

Data Source

PatentUS12057274B2Packaging structures for electronic elements and solid electrolytic capacitor elements and methods thereof

Publication Date: 2024.08.06 ZOWIE TECH CORP

AI summary

This invention describes packaging structures and methods for electronic devices, especially for solid electrolytic capacitor devices. A packaging structure applies at least two protective substrates to sandwich one or multiple capacitor elements stacked together in between with an insulating material surrounding the capacitor elements also in between the protective substrates. Each protective substrate comprises an anodic conductor pad and a cathodic conductor pad. The anodic conductor pad is electrically connected to an external anode terminal, which is in turn electrically connected to the tip face of the anode end of the capacitor element. The cathodic pad is electrically connected to the cathode of the capacitor element as well as to an external cathode terminal. For quantity production, the basic concept includes sandwiching hundreds of capacitor elements in between large thin protective substrates and bonding them to the conductor pads on the protective substrates; then filling in the insulating material by a capillary filling process; then curing the assembly into a first intermediate assembly. A second intermediate assembly is then made by cutting slots over the first intermediate assembly to expose the anodic and cathodic ends of each capacitor device for subsequent metal depositions to make the external terminals.