Battery Cell Electrode Tab Structure for Low-Strain Laser Welding
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Solution Overview
Problem
Conventional methods for forming laser-welded portions between electrode tabs and current collectors in battery cells are inadequate, leading to suboptimal joining structures that may result in clearance issues and thermal strain during welding.
Innovation Solution
A battery cell design featuring a stacking structure of metal foils with burring-processed portions, where laser welding is performed between or adjacent to these portions to ensure close contact and secure bonding, eliminating the need for compression and minimizing thermal strain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional joining structures are used, then the electrode tab and current collector can be joined, but the laser-welded portion is insufficient and may result in clearance issues and thermal strain
Solution Approach 1:
The metal foils are pre-compressed before laser welding to ensure close contact between the electrode tab and current collector. This preliminary compression eliminates clearance issues before the welding process begins, allowing the laser to effectively join the surfaces without gaps that would compromise weld quality or cause thermal strain.
2Reliability
If compression is applied to ensure contact, then bonding quality improves, but the load requirement increases
Solution Approach 1:
The patent replaces heavy mechanical compression with a localized pre-compression mechanism applied only at the laser-welded portion. This allows sufficient contact pressure to be achieved at the welding zone without subjecting the entire electrode tab assembly to high loads, thereby improving bonding quality while minimizing the overall force requirement.
3Ease of manufacture
If the electrode tab structure is simplified, then manufacturing becomes easier, but contact between metal foils may be insufficient
Solution Approach 1:
The electrode tab is designed with a localized compression structure at the specific region where contact with the current collector is required. Rather than complicating the entire electrode tab structure, the invention applies a targeted local feature that ensures adequate metal foil contact only where needed for welding, maintaining simplicity elsewhere while achieving precise contact where critical.
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 results in an excellent laser-welded portion with improved contact between metal foils, reducing the risk of clearance and thermal strain, while allowing for efficient and secure bonding with a smaller load, enhancing the overall performance and reliability of the battery cell.
Implementation Method 1
a laser-welded portion that joins the electrode tab and the current collector is formed
Data Source
AI summary
A battery cell includes: a case including a main body provided with an opening, and a sealing plate that seals the main body; an electrode assembly accommodated in the case and having an electrode tab; and a current collector joined to the electrode tabs. The electrode tab has a stacking structure of metal foils, and a plurality of burring-processed portions along a stacking direction of the metal foils are formed in the electrode tab. A laser-welded portion that joins the electrode tab and the current collector is formed at least in a region located between the plurality of burring-processed portions or at least in a region adjacent to the plurality of burring-processed portions.