Lithium Battery Tab Design for Electrode Warping
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Solution Overview
Problem
Lithium secondary batteries face issues with electrode warping and wrinkling due to active material application, leading to non-uniform contact between electrodes, which affects battery reaction uniformity, safety, and lifetime.
Innovation Solution
The battery design incorporates electrode tabs with two portions of different widths, where the narrower portion connects to the electrode and the wider portion protrudes laterally, minimizing warping and ensuring uniform contact, while the wider portion enhances electrical energy transfer and heating properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the active material is applied thicker on the active material border through coating process, then the coating process is simplified, but the electrode warps due to non-uniform thickness distribution
Solution Approach 1:
The tab junction is designed with a localized protruding structure at the border region where active material is applied. This local structural modification allows the electrode to accommodate non-uniform active material thickness without warping, as the protruding tab junction provides a stress relief point that prevents deformation propagation across the entire electrode.
2Shape
If the electrode is pressed to eliminate warping, then electrode flatness is improved, but the entire electrode group becomes distorted due to non-uniform contact
Solution Approach 1:
The protruding tab junction creates a localized contact interface between electrodes in the electrode group. This local structural feature ensures uniform contact pressure distribution at the critical border region where active material is applied, preventing non-uniform compression and maintaining the structural integrity and uniformity of the entire electrode group during stacking and operation.
3Ease of manufacture
If electrodes are not uniformly contacted in the electrode group, then manufacturing is simplified, but lithium deposition occurs and safety is compromised
Solution Approach 1:
The tab junction is pre-formed with a protruding structure that anticipates and prevents non-uniform contact during electrode assembly. This preliminary structural preparation ensures that when electrodes are stacked, the protruding tab junctions create consistent contact points that distribute compression forces uniformly, preventing the formation of gaps that would lead to lithium deposition and safety issues.
Data Source
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Figure 3~4
AI summary
This invention relates to a lithium secondary battery, the tab shape of which is improved, thus increasing the safety and improving the electrical properties thereof. The lithium secondary battery includes an electrode group composed of a first electrode, a second electrode, and a separator disposed between the first electrode and the second electrode, a first electrode tab connected to the first electrode, and a second electrode tab connected to the second electrode. The first electrode tab includes a first portion connected to the first electrode and a second portion, which is not the first portion, the width of the first portion being less than the width of the second portion.