Capacitor Carrier Assembly Encapsulating Tin Whisker Growth
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Solution Overview
Problem
Capacitors in electronic devices face issues with tin whisker growth at connection points, leading to potential electrical shorts, which existing prevention methods like coatings and soldering are costly in terms of materials and labor.
Innovation Solution
A capacitor carrier with encapsulated joint interfaces that retains whiskers within a closed space, preventing contact with the PCB and using identical housing portions to simplify manufacturing and reduce costs, while providing secure mechanical and electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coatings are applied to capacitor leads to prevent tin whisker growth, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The patent extracts the capacitor leads and connection terminals from direct exposure to the environment by enclosing them within a housing structure. This physical enclosure replaces the need for costly protective coatings on the leads themselves, while still preventing tin whisker growth by isolating the affected areas.
Solution Approach 2:
The housing structure acts as an intermediary barrier between the capacitor leads/connection terminals and the external environment. Instead of applying coatings directly to the leads, the housing provides indirect protection, achieving the same reliability goal through a different mechanism that reduces manufacturing complexity.
2Reliability
If soldering processes are used to form electrical connections to prevent tin whiskers, then reliability is improved, but manufacturing cost and complexity increase
Solution Approach 1:
The patent extracts the connection interfaces from direct exposure by enclosing them within the housing structure. This allows for simpler mechanical connections without requiring complex soldering processes, while still preventing tin whisker formation through physical enclosure.
Solution Approach 2:
The housing structure provides a simple, cost-effective solution that replaces expensive and complex soldering processes. The housing itself becomes the primary protective element, eliminating the need for additional complex manufacturing steps.
3Device complexity
If capacitor leads are directly connected to PCB without enclosure, then device complexity is reduced, but harmful effects from tin whiskers increase
Solution Approach 1:
The patent segments the capacitor assembly from the main device by introducing a separate housing structure. This segmentation isolates the potential harmful effects of tin whisker growth to a contained area, preventing them from affecting the rest of the device while adding minimal overall complexity.
Solution Approach 2:
The patent converts the potential harm of tin whisker growth into a contained, controlled environment within the housing. By enclosing the connection interfaces, any tin whisker growth is confined to a small space where it cannot cause electrical shorts, effectively neutralizing the harmful effect.
Data Source
AI summary
A capacitor carrier assembly includes a carrier, a capacitor disposed in the carrier and electrically conductive connection terminals. The connection terminals support the carrier with respect to another electronic component or device such as a printed circuit board, retain individual carrier portions in an assembled configuration, and provide an electrical connection between the capacitor and the electronic component. Each connection terminal includes an elastic member that protrudes from a surface of the connection terminal and engages the carrier, and regions of serrations provided on opposed edges of the terminal that engage the carrier, and a flange that protrudes from the surface in a direction perpendicular to the first surface. An edge of the flange includes an insulation displacement contact (IDC) joint for connection to the capacitor leads.