Current Sensing Resistor with Electroplated Detection Terminal
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Solution Overview
Problem
Current sensing resistors face issues with mechanical strength and electrical performance due to temperature-related solder displacement and risk of short circuits during high-temperature operations, leading to resistance variations and detection accuracy loss.
Innovation Solution
A current sensing resistor design featuring a conductive body with receiving blind holes for a detection terminal, where the terminal is fixed using a metal riveting method, enhancing mechanical strength and preventing solder melting, with adjustable width and thickness for improved mechanical force and using copper or copper alloys for the electrode portions and detection terminal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If surface soldering processes are used to connect electrodes to PCB, then electrical connectivity is achieved, but the detection terminal displaces under high temperature causing resistance variation and loss of detection accuracy
Solution Approach 1:
The patent replaces the traditional mechanical soldering connection with an electroplated metal layer connection. The detection terminal is electroplated with a metal layer that directly bonds to the electrode, eliminating the need for separate solder joints that are prone to displacement under thermal stress. This substitution of connection mechanism resolves the terminal position stability issue while maintaining electrical connectivity.
Solution Approach 2:
The patent employs a composite structure where the detection terminal is composed of a base material (copper or copper alloy) electroplated with a different metal layer (such as nickel or tin). This composite material approach provides both mechanical strength for position stability and electrical conductivity for connectivity, while the electroplated layer offers resistance to thermal displacement and corrosion.
2Reliability
If solder is coated on electrodes and connected by surface mount technique, then electrical connection is established, but high-temperature operation causes solder to melt leading to resistance variation and potential short circuits
Solution Approach 1:
The patent eliminates the solder material entirely by using direct electroplating of the detection terminal with a metal layer that forms a permanent metallurgical bond with the electrode. This replaces the temporary solder joint with a permanent plated connection that can withstand high operating temperatures without melting or deforming, thus preventing resistance variation and short circuits.
Solution Approach 2:
The patent changes the material parameters of the connection layer by using electroplated metals with much higher melting points than solder. The electroplated metal layer (such as nickel or tin) maintains structural integrity and electrical properties at high temperatures, fundamentally changing the temperature resistance parameter of the electrical connection.
3Ease of manufacture
If traditional soldering methods are used, then manufacturing simplicity is maintained, but mechanical strength is insufficient leading to position changes under thermal and mechanical stress
Solution Approach 1:
The patent replaces the two-step process of soldering with a single electroplating step that simultaneously provides both mechanical bonding and electrical connectivity. The electroplating process deposits a metal layer that mechanically interlocks with the electrode surface, creating a stronger bond than solder while simplifying the manufacturing process by eliminating separate soldering operations.
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 provides improved mechanical strength and electrical performance by preventing solder melting and position changes, ensuring long-term mechanical shock resistance and maintaining detection accuracy, while reducing the risk of short circuits and resistance variations.
Implementation Method 1
a detection terminal disposed on the receiving blind hole. The detection terminal includes a base fixed in the receiving blind hole
Implementation Method 2
Each of the pair of electrode portions around the terminal pin is punched to form an extrusion portion encircling the neck portion. The extrusion portion clamps the head portion and the neck portion and fixes the base in the receiving blind hole.
Data Source
AI summary
A current sensing resistor includes a conductive body comprising a resistor portion and a pair of electrode portions connecting to two ends of the resistor portion, a receiving blind hole disposed on a top surface of each of the pair of electrode portions, and a detection terminal disposed on the receiving blind hole. The detection terminal includes a base fixed in the receiving blind hole and a terminal pin protruding from the top surface.