Power Relay Terminal Tabs Segmentation for Heat Management
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Solution Overview
Problem
High-capacity power relays face challenges in increasing terminal tab sizes to manage higher currents, leading to increased product size and heat generation, which affects reliability and space efficiency.
Innovation Solution
The power relay design features input/output terminal tabs with the same thickness and width as control terminal tabs, formed by a single U-shaped metal piece, allowing for compact arrangement and efficient heat management, with each input/output terminal tab capable of handling a rated current of 30 A to 100 A.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the cross-sectional area of terminal tabs is increased to handle higher currents, then heat generation is reduced and connection reliability is improved, but the product size increases
Solution Approach 1:
The terminal tab structure is segmented into multiple thin tabs arranged in parallel (first and second terminal tabs per input/output terminal element). This segmentation allows the current to be distributed across multiple smaller cross-sectional areas while maintaining the same current-carrying capacity, thereby reducing heat generation without increasing the overall product size.
Solution Approach 2:
Instead of increasing the cross-sectional area in the planar direction (width), the invention utilizes the thickness direction by stacking multiple thin terminal tabs (first and second tabs) vertically. This dimensional transition allows achieving the required current-carrying capacity through increased number of parallel paths rather than increasing individual tab size.
2Loss of energy
If the width and thickness of terminal tabs are increased to decrease connection resistance, then heat generation is reduced, but the product size increases
Solution Approach 1:
The terminal connection is segmented into multiple parallel paths formed by first and second terminal tabs. This segmentation reduces the current density in each individual tab, thereby reducing Joule heating (I²R losses) without requiring an increase in the overall product size.
Solution Approach 2:
Multiple thin terminal tabs (first and second tabs) are combined in parallel to achieve the same current-carrying capacity and heat dissipation performance as a single large terminal tab, while maintaining a compact product size.
3Reliability
If larger terminal tabs are used to handle higher currents, then connection reliability is improved, but the number of terminal elements increases
Solution Approach 1:
Each input/output terminal element is segmented into two thin terminal tabs (first and second tabs) arranged in parallel. This segmentation provides multiple current paths within each terminal element, improving current distribution and connection reliability without requiring an excessive number of separate terminal elements.
Solution Approach 2:
The terminal tabs have different local qualities: the first and second terminal tabs are optimized for current conduction with smaller cross-sectional areas, while the third terminal tab provides mechanical support and structural stability. This local differentiation allows achieving reliable connections with optimized current distribution.
Data Source
AI summary
A power relay having terminal tabs includes an on-off contact element having at least one movable contact and at least one stationary contact, an on-off drive element, at least two pairs of input/output terminal tabs, and at least one pair of control terminal tabs. The on-off drive element makes the movable contact come into contact with or separated from the stationary contact. The two pairs of input/output terminal tabs are electrically connected to at least one pair of input/output portions of the on-off contact element. The one pair of control terminal tabs is electrically connected to control terminal portions of the on/off drive element. Each of the input/output portions is electrically connected to two of the input/output terminal tabs, which are arranged side-by-side in their thickness direction and in vicinity with each other. The input/output terminal tabs and the control terminal tabs have a same thickness and width.