Stacked Battery Tab Grouping for Stable Ultrasonic Welding
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Solution Overview
Problem
In stacked lithium-ion batteries, the existing methods for welding current collection tabs to lead terminals require determining optimum welding conditions each time the number of tabs changes, leading to potential tab breakage and instability, especially when increasing the number of layers.
Innovation Solution
The method involves forming groups of current collection tabs that can be bonded simultaneously under established conditions, with positions of these groups displaced longitudinally or transversally, allowing for stable welding without breaking tabs, and using differentiated tab lengths and lead terminal profiles to accommodate varying numbers of tabs without altering welding conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of current collection tabs is increased to increase battery capacity, then the energy density and capacity of the battery are improved, but the current collection tabs are more likely to be cut and broken during welding due to excessive welding energy input
Solution Approach 1:
The patent divides the current collection tabs into multiple groups based on their positions in the stacked battery. Each group contains a specific number of tabs that are welded simultaneously using separate welding electrodes. This segmentation allows the welding process to be divided into manageable portions, preventing excessive welding energy from being applied to all tabs at once, thereby reducing the risk of tab breakage while still accommodating a large total number of tabs.
2Quantity of substance
If the number of current collection tabs is increased to increase battery capacity, then the energy density is improved, but the welding conditions must be re-determined for each configuration change, increasing manufacturing complexity
Solution Approach 1:
The patent designs the welding apparatus with multiple welding electrodes that can be universally applied to different configurations of current collection tabs. The welding conditions (such as ultrasonic welding parameters) are established once for each group type and can be reused across different battery designs. This universal approach allows the same welding system to handle various numbers of tabs without requiring re-determination of welding conditions for each configuration change.
Solution Approach 2:
The patent changes the structural parameter of the welding apparatus by providing multiple welding electrodes with specific arrangements. Instead of changing welding parameters (energy, time, pressure) when the number of tabs changes, the system changes the physical configuration of the welding apparatus itself. This allows different groups of tabs to be welded simultaneously using the same standardized welding parameters, reducing the need to re-determine welding conditions.
3Length of moving object
If the thickness of current collection tabs is reduced to achieve thinner battery profiles, then the battery can be downsized and made flatter, but the tabs become more vulnerable to breaking during welding
Solution Approach 1:
By dividing the tabs into smaller groups that are welded separately, the patent reduces the total welding energy input required for each individual welding operation. This segmentation allows thin tabs to be welded with lower energy per tab, preventing breakage while still achieving secure connections. The thin tabs can be welded in smaller batches rather than all at once, reducing the cumulative stress on each tab.
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 approach enables stable welding and connection of current collection tabs regardless of the number of tabs, allowing for increased layers without damaging them, and improves the reliability of the battery by maintaining consistent welding conditions and reducing the risk of tab breakage.
Implementation Method 1
the positive electrode current collection tabs and the negative electrode current collection tabs are bonded respectively to a positive electrode lead terminal and a negative electrode lead terminal by an ultrasonic welding apparatus
Data Source
Figure 1
Figure 2~10
Figure 3A~3B
AI summary
A method for production of a stacked battery having a plurality of positive electrode current coll ection tabs and a plurality of negative electrode current collection tabs drawn out from a stacked member formed by laying positive electrodes and negative electrodes alternately one on the other with separators interposed between them and bonded respectively to a positive lead terminal and a negative lead terminal comprises a step of determining in advance a simultaneously bondable number, or the number of positive electrode current collection tabs and the number of negative electrode current collection tabs that can be laid one on the other and collectively bonded, and bonding conditions for bonding them and a step of forming groups of current collection, tabs, each group being formed by laying a number of current collection tabs not exceeding the simultaneously bendable number one on the other, displacing the bonding positions of the groups of positive electrode current collection tabs or those of negative electrode current collection tabs relative to each other in the direction of drawing out the positive electrode current collection tabs or the negative electrode current collection tabs, whichever appropriate, or in a direction perpendicular to the direction on the surface of the positive lead terminal or the negative lead terminal, whichever appropriate, and collectively bonding the positive electrode current collection tabs or the negative electrode current collection tabs of each group under the bonding conditions.