Rechargeable Battery Terminal with Segmented Copper Steel Materials
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Solution Overview
Problem
Conventional rechargeable batteries face challenges in achieving both strong weldability of the electrode terminal with the lead tab inside the cap plate and a robust fastening force with a nut or bus bar outside the cap plate, often resulting in loose connections due to vibration, temperature, or impact.
Innovation Solution
The electrode terminal is designed with a terminal through-out portion made of copper or aluminum for excellent weldability and a terminal plate and fastening portion made of steel, connected via caulking and welding respectively, to enhance weldability inside the cap plate and fastening force outside, using a bus bar and nut.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the electrode terminal is made of a single material to simplify structure, then manufacturing complexity is reduced, but it cannot simultaneously achieve strong weldability with lead tab (copper/aluminum property) and robust fastening force with nut (steel property)
Solution Approach 1:
The electrode terminal is divided into three distinct segments: terminal through-out portion (copper or aluminum for weldability), terminal plate (transition material), and terminal fastening portion (steel for fastening strength). Each segment is optimized for its specific function, resolving the contradiction between manufacturing simplicity and connection reliability by allowing different materials in different regions.
Solution Approach 2:
The electrode terminal uses a composite structure combining copper/aluminum, steel, and intermediate materials. The terminal plate may include a copper layer and a steel layer formed in sequence, creating a composite material that bridges the electrical conductivity needs (copper) and mechanical strength needs (steel) of the different connection points.
2Ease of manufacture
If the electrode terminal uses copper or aluminum for weldability, then weldability with lead tab is improved, but fastening force with nut outside cap plate deteriorates
Solution Approach 1:
The electrode terminal applies local quality by making the terminal through-out portion (inside cap plate) of copper or aluminum for excellent weldability with lead tab, while the terminal fastening portion (outside cap plate) is made of steel for robust fastening force with nut. The terminal plate in between serves as a transition zone, ensuring each region has the material properties optimized for its specific function.
3Strength
If the electrode terminal uses steel for fastening force, then fastening force with nut is improved, but weldability with lead tab deteriorates
Solution Approach 1:
The electrode terminal structure assigns steel material property locally to the terminal fastening portion where high fastening force is needed, while the terminal through-out portion uses copper or aluminum where weldability is critical. This localized material assignment resolves the contradiction by ensuring steel provides fastening strength only where needed, without compromising weldability at the lead tab connection point.
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
This configuration ensures strong and durable connections, preventing loosening and maintaining low contact resistance even under stress, thereby improving the overall performance and reliability of the rechargeable battery.
Implementation Method 1
The terminal through-out portion and the terminal plate may be connected to each other by caulking
Implementation Method 2
the terminal plate and the terminal fastening portion may be connected to each other by welding
Data Source
AI summary
A rechargeable battery includes an electrode assembly including wound positive and negative electrodes with a separator therebetween, a case configured to contain the electrode assembly, a cap plate configured to seal an opening of the case, the cap plate including a terminal hole therethrough, an electrode terminal through the terminal hole of the cap plate, the electrode terminal including a terminal through-out portion extending through the terminal hole, a terminal plate connected to the terminal through-out portion outside the case, and a fastening portion including a terminal fastening portion connected to the terminal plate, and a lead tab inside the case, the lead tab connecting the terminal through-out portion of the electrode terminal to the electrode assembly.