Stack Battery Terminal Segmentation for Uniform Connection Resistance
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Solution Overview
Problem
Stack type lithium ion batteries experience poor weldability and variations in connection resistance between electrode plates and current collector terminals, leading to uneven charge-discharge conditions and poor battery cycle performance, especially at high rates.
Innovation Solution
A stack type battery configuration with plate-shaped current collector terminals and tabs made of metal foil, where the tabs are welded to each other and to the terminals, ensuring uniform connection resistance by joining them at specific locations to prevent variations in connection resistance values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of positive and negative electrode plates is increased to achieve higher capacity, then battery capacity increases, but the thickness of current collector terminals must be increased, which worsens weldability and increases variations in connection resistance
Solution Approach 1:
The current collector terminal is divided into multiple terminal portions (first terminal portion and second terminal portion) that are positioned at different locations. This segmentation allows each terminal portion to be optimally positioned relative to the electrode plates, reducing the thickness required while maintaining good weldability and uniform connection resistance across all welding locations.
Solution Approach 2:
Instead of increasing terminal thickness in the vertical dimension to handle higher capacity, the invention introduces additional terminal portions in the horizontal dimension (different spatial locations). This dimensional approach allows current to be collected from multiple points, effectively handling higher capacity without compromising weldability or connection resistance uniformity.
2Ease of manufacture
If ultrasonic welding is performed on a large number of current collector tabs to a thick current collector terminal, then all tabs can be connected, but variations in connection resistance values occur due to thickness difference and simultaneous welding of many tabs
Solution Approach 1:
The terminal is segmented into multiple terminal portions positioned at different locations. This allows the welding process to be distributed across multiple smaller welding zones rather than attempting to weld all tabs to a single thick terminal, thereby maintaining consistent connection resistance values while preserving manufacturing efficiency.
3Ease of manufacture
If connection resistance values vary between electrode plates and terminal, then welding is easier to perform, but uneven current distribution occurs during high rate charge-discharge, leading to partial overdischarge or overcharge
Solution Approach 1:
By segmenting the terminal into multiple terminal portions positioned at different locations, the invention ensures that all electrode plates maintain uniform connection resistance values. This uniformity prevents uneven current distribution during high rate charge-discharge operations, eliminating partial overdischarge or overcharge conditions and improving battery cycle performance while maintaining ease of welding.
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 uniform current flow and prevents partial overdischarge or overcharge, thereby minimizing battery cycle performance deterioration even at high charge-discharge rates.
Implementation Method 1
The plurality of positive electrode tabs are overlapped with each other and ultrasonic welded to a positive electrode current collector terminal, while the plurality of negative electrode tabs are likewise overlapped with each other and are ultrasonic welded to a negative electrode current collector terminal
Data Source
AI summary
A stack type battery has positive electrode current collector tabs (11) overlapped with each other and welded to a positive electrode current collector terminal (15), and negative electrode current collector tabs (12) overlapped with each other and welded to a negative electrode current collector terminal (16). The positive electrode current collector tabs (11) existing between the positive electrode plates (1) and an end part (15a) of the positive electrode current collector terminal (15) that is on the positive electrode plate (1) side are welded to each other and/or the negative electrode current collector tabs (12) existing between the negative electrode plates (2) and an end part (16a) of the negative electrode current collector terminal (16) that is on a negative electrode plate (2) side are welded to each other.