Capacitor Lid Venting for Accurate Sealing Resin Height

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Solution Overview

Problem

Conventional capacitors face challenges in providing an index part due to size constraints, and the dimensional accuracy of the resin surface height is compromised by variations in sealing resin amount and bubble accumulation, which is exacerbated by the need for heat dissipation in vehicular applications.

Innovation Solution

A capacitor design that includes a lid with through parts for controlled resin pouring and bubble expulsion, along with index parts for precise resin amount adjustment, ensuring accurate resin surface height and improved heat dissipation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sealing resin is poured into the case to seal the capacitor element, then the capacitor element is sealed and protected, but the resin surface height becomes inaccurate due to variations in the amount of poured resin

Engineering Contradiction:
Improvesealing protectionVSAvoidresin surface height accuracy
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent introduces a lid as an intermediary component between the case and the sealing resin. The lid has a through part that controls where the resin is poured and how it fills the case. This mediator structure ensures that the resin surface height is determined by the lid position rather than by variations in pouring amount, thus maintaining manufacturing precision while still providing reliable sealing protection.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If bubbles are allowed to accumulate during resin pouring, then the resin filling process is simple, but the resin surface height decreases and the sealing resin becomes thinner than intended

Engineering Contradiction:
Improveresin pouring process simplicityVSAvoidresin surface height and thickness
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent extracts bubbles from the resin filling process by providing a designated escape path through the lid structure. The through part of the lid serves as a bubble vent that allows trapped air to escape during resin pouring, preventing bubble accumulation that would otherwise displace resin and reduce surface height. This maintains both manufacturing simplicity and resin thickness precision.

Inventive Principle:
Principle #2Taking out (Extraction)

3Temperature

If the resin surface height is made accurate for heat dissipation components, then heat dissipation effectiveness is improved, but the process time increases due to multiple pouring operations

Engineering Contradiction:
Improveheat dissipation effectivenessVSAvoidprocess time
Core Design Contradiction:
TemperatureVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-positioning the lid with its through part before resin pouring. This preliminary setup establishes the exact resin surface height and pouring control mechanism in advance, eliminating the need for multiple pouring operations to achieve accurate height. The lid structure pre-defines the filling endpoint, allowing single-pour accuracy that reduces process time while maintaining heat dissipation effectiveness.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4685831A1Capacitor and method for manufacturing capacitor
Publication Date: 2026.01.28 NICHICON CORP
  • EP4685831A1 patent drawingFigure 1
  • EP4685831A1 patent drawingFigure 2
  • EP4685831A1 patent drawingFigure 3

AI summary

To provide a capacitor having reduced variations in the amount of a sealing resin and having an upper surface with improved height dimensional accuracy. The capacitor (1) includes: a capacitor element (10); a case (50) that has an open part (51f) and houses the capacitor element (10); a lid (60) that has a through part (61aa to 61af) and is disposed at the open part (51f) with the capacitor element (10) being housed in the case (50); and a sealing resin (70) that is poured into the case (50) to seal the capacitor element (10).