Metal Case Capacitor Insulation Housing for High Withstanding Voltage
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Solution Overview
Problem
Metal case capacitors experience poor insulation withstanding voltage between the metal case and P/N electrodes due to reduced insulation distance and the presence of conductive foreign substances, leading to potential short circuits.
Innovation Solution
A metal case capacitor with a net-shaped plastic insulation housing that has multiple openings, allowing for strong coupling with a filler to maintain accurate gap thickness and improve durability, featuring insulation gap formation members in a pulse wave or stepped shape to ensure complete filling without air voids and enhance adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a metal case is used for the capacitor housing, then heat dissipation performance is improved, but insulation withstanding voltage between the metal case and P/N electrodes deteriorates due to reduced insulation distance and conductive foreign substances
Solution Approach 1:
A plastic insulation housing is introduced as an intermediary component between the metal case and the capacitor element. This plastic housing serves as a mediator that provides electrical insulation while allowing the metal case to maintain its heat dissipation function. The insulation housing includes insulation gap formation members that maintain proper spacing and prevent direct contact between conductive parts.
Solution Approach 2:
The capacitor employs a composite structure combining metal case material (for heat dissipation) with plastic insulation material (for electrical isolation). This composite approach allows both thermal performance and electrical insulation requirements to be satisfied simultaneously by using different materials in appropriate locations.
2Reliability
If molding material is used to fill the case, then insulation is improved, but manufacturing complexity increases due to the need for precise insulation gap maintenance and foreign substance control
Solution Approach 1:
The insulation function is segmented into separate components: the plastic insulation housing, insulation gap formation members, and filler material. This segmentation allows each component to be manufactured and inspected independently, reducing the complexity of the overall molding process while maintaining insulation reliability.
Solution Approach 2:
The insulation housing and gap formation members are pre-formed with specific geometries that automatically maintain proper insulation gaps. This preliminary preparation of insulating structures eliminates the need for complex real-time gap control during the molding process, simplifying manufacturing while ensuring insulation performance.
3Reliability
If the insulation housing is made solid without openings, then insulation performance is improved, but heat dissipation performance deteriorates
Solution Approach 1:
The insulation housing features localized openings in specific regions where electrical insulation is not compromised, allowing heat to escape. The plastic material provides insulation where needed while strategic openings are positioned to maintain thermal pathways, achieving both insulation and heat dissipation objectives through spatially differentiated properties.
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 effectively increases the insulation withstanding voltage, maintains gap accuracy, and improves durability against shock, reducing the risk of short circuits while maintaining excellent heat dissipation characteristics.
Implementation Method 1
a filler permeating in a gel or liquid state into a space between the capacitor module 10 and the metallic external case 20 and then cured
Data Source
AI summary
The present disclosure relates to a metal case capacitor that includes: a capacitor module (10) including a capacitor device, a first busbar (1) electrically connected with a thermally-sprayed surface of the capacitor device and having a first lead terminal (1a) on an exposed side, a second busbar (2) electrically connected with the other thermally-sprayed surface of the capacitor device and having a second lead terminal (2a) on an exposed side, and an insulating sheet disposed between the first busbar (1) and the second busbar (2); a metallic external case (20) having a space; a plastic insulating member positioned between the capacitor module (10) and the metallic external case (20) and insulating the capacitor module (10) and the metallic external case (20) from each other; and a filler permeating in a gel or liquid state into a space between the capacitor module (10) and the metallic external case (20).