Hybrid Polymer Aluminum Capacitor Impregnation for Large Winding Elements

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Solution Overview

Problem

Existing hybrid polymer aluminum electrolytic capacitors face limitations in size due to increased equivalent series resistance (ESR) and inefficient polymer impregnation, preventing the construction of capacitors with diameters over 10 mm and heights over 12 mm, which leads to performance reduction and potential short-circuits from compensation currents.

Innovation Solution

The design incorporates multiple tabs for electrical contact to minimize resistance and uses a method of applying pressure pulses during polymer impregnation to ensure homogeneous coverage of the winding element, allowing for capacitors with diameters over 10 mm and heights over 12 mm, and ensures all polymer regions are adjacent to the cathode foil to prevent compensation currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If the diameter and height of the winding element are increased to achieve larger capacitor sizes, then the capacitance and energy storage capacity are improved, but the equivalent series resistance (ESR) increases and polymer impregnation becomes inefficient

Engineering Contradiction:

ImprovecapacitanceVSAvoidESR

Core Design Contradiction:

Quantity of substanceVSReliability

Solution Approach 1:

The patent divides the single large winding element into multiple smaller winding elements connected in parallel. Each small winding element maintains optimal dimensions for efficient polymer impregnation and low ESR, while the parallel connection achieves the desired total capacitance. This segmentation resolves the contradiction by allowing large capacitance without the ESR penalty of a single large winding.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent uses pressure pulses (pneumatic/hydraulic method) to impregnate the polymer dispersion into the winding element. By applying periodic pressure pulses during impregnation, the viscous polymer dispersion is forced to penetrate deeply and uniformly throughout the winding structure, overcoming the resistance to flow and ensuring complete saturation even in large dimensions.

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Quantity of substance

If the height of the winding element is increased beyond 12 mm, then the capacitance is improved, but the polymer dispersion cannot penetrate completely due to high viscosity and capillary limitations

Engineering Contradiction:

ImprovecapacitanceVSAvoidpolymer impregnation

Core Design Contradiction:

Quantity of substanceVSEase of manufacture

Solution Approach 1:

The patent applies periodic pressure pulses during the polymer impregnation process. Instead of continuous pressure, the periodic pulsing creates alternating phases of polymer infiltration and solvent evaporation, which facilitates deep penetration into the winding structure. This periodic action overcomes the limitations of capillary pressure and polymer viscosity, enabling complete impregnation of high winding elements.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent changes the pressure parameter during impregnation by applying periodic pressure pulses. The pressure varies from atmospheric to several bar during the process, which dynamically alters the flow characteristics of the polymer dispersion and enables penetration into regions that would be inaccessible under constant atmospheric pressure.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If polymer regions are not adjacent to the cathode foil in large diameter capacitors, then the manufacturing flexibility is improved, but compensation currents are generated during fast charging and discharging

Engineering Contradiction:

Improvewinding design flexibilityVSAvoidrobustness against fast charging

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent ensures that polymer regions are specifically positioned adjacent to the cathode foil in the winding structure. This local arrangement creates a potential gradient that prevents compensation currents during fast charging and discharging. By controlling the local quality of polymer placement rather than uniform distribution, the design achieves both manufacturing flexibility and electrical reliability.

Inventive Principle:

Principle #3Local quality

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 enables the construction of capacitors with improved ESR and ripple current capability, increased reliability, and extended lifetime by reducing metal resistance and preventing compensation currents, while ensuring efficient polymer distribution within the winding element.

Implementation Method 1

The polymer dispersion is sucked into the winding element by the wetting and capillary effects of the paper

Methodology Applied

Scientific EffectCapillary action: Capillary Action

Implementation Method 2

applying pressure pulses to the flooded winding element

Methodology Applied

Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentUS11823847B2Hybrid polymer aluminum electrolytic capacitor and method of manufacturing a capacitor

Publication Date: 2023.11.21 TDK ELECTRONICS AG

AI summary

A hybrid polymer aluminum electrolytic capacitor and a method for manufacturing a capacitor are disclosed. In an embodiment a method for manufacturing a capacitor includes winding an anode foil, separators and a cathode foil around an axis to form a winding element, flooding the winding element with a polymer dispersion, wherein the polymer dispersion contains electrically conductive solid polymer particles or a polymer powder and a solvent and applying pulses of overpressure to the flooded winding element.