Tabless Roll Capacitor Stack Design
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Solution Overview
Problem
The assembly and interconnection of roll capacitors to form capacitor chains are labor-intensive, expensive, and prone to human error, with conductive tabs subject to mechanical stress and cyclic thermal expansion, requiring additional space in containment housings.
Innovation Solution
The design of roll capacitors with inner and outer electrode strips separated by dielectric strips, where the electrode strips have exposed ends for direct stacking contact, eliminating the need for interconnection tabs and allowing for series and parallel connections by simple stacking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conductive tabs are used to interconnect roll capacitors, then capacitor chains can be formed, but the assembly becomes labor-intensive and expensive
Solution Approach 1:
The patent removes the conductive tabs from the capacitor structure entirely. Instead of having tabs extending from the capacitor ends for interconnection, the electrode strips are designed with exposed ends that make direct contact with adjacent capacitors when stacked, eliminating the need for separate interconnection elements and simplifying the assembly process
Solution Approach 2:
The interconnection function is merged into the capacitor structure itself. The electrode strips serve dual purposes: as functional electrical components and as interconnection elements. By stacking capacitors with exposed electrode ends, the capacitors interconnect directly through their own structural elements rather than requiring separate tabs
2Ease of operation
If conductive tabs extend beyond capacitor ends, then interconnection is achieved, but additional chamber width is required
Solution Approach 1:
The patent transitions from a horizontal interconnection approach (tabs extending sideways) to a vertical stacking approach. Capacitors are stacked in the vertical dimension with electrode ends contacting each other, eliminating the need for horizontal tab extensions and reducing the required chamber width
3Ease of manufacture
If conductive tabs are used for interconnection, then capacitor chains can be assembled, but mechanical stress and thermal expansion fatigue the tabs
Solution Approach 1:
The vulnerable conductive tabs are completely removed from the design. The exposed electrode strip ends directly contact adjacent capacitors, eliminating the separate interconnection element that was subject to mechanical stress and thermal fatigue
Solution Approach 2:
The patent design anticipates and prevents the fatigue problem by using direct electrode contact rather than separate tabs. The exposed electrode ends are designed to make direct contact with adjacent capacitors, creating a more robust connection that withstands mechanical stress and thermal cycling without the fatigue issues that plague tab-based interconnections
Data Source
Figure 1~4
Figure 5~7
Figure 8~10
AI summary
A capacitor (20A-E) formed as a roll of inner and outer electrode strips (21, 23) alternating with inner and outer dielectric strips (22, 24). Each of the dielectric strips (22, 24) is shorter than an inwardly adjacent one of the electrode strips (21, 23) at a radially outer end thereof (21 E, 23E). This exposes the radially outer end of each electrode strip on respectively different portions of an outer side surface (26, 28) of the capacitor. The exposed ends of the electrode strips may be arranged on opposite sides of the capacitor, such that stacking the capacitors interconnects them either in parallel, in series, or in combinations thereof in different embodiments.