Pouch Battery Electrode Tab Bend Structure for Swelling Reliability
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Solution Overview
Problem
Secondary batteries face disconnection issues due to swelling of the electrode assembly, which is exacerbated by the need to increase the length of the electrode tab to prevent disconnection, leading to unnecessary size increases.
Innovation Solution
The secondary battery design incorporates electrode tabs with a bent part featuring a first bent surface connected to the coupling part at a first-b angle greater than the second-b angle, allowing for increased length without expanding the battery size, by unfolding when the assembly swells, and using a method that adjusts these angles during manufacturing to secure the tab's margin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the length of the electrode tab is increased to prevent disconnection during swelling, then the reliability is improved, but the length of the stationary object (battery) increases
Solution Approach 1:
The electrode tab is configured with a bent part that extends in a direction substantially perpendicular to the stacking direction of the electrode assembly. This dimensional change allows the tab to achieve sufficient length for reliability without increasing the battery's overall length, as the extension occurs in a different spatial dimension.
Solution Approach 2:
The electrode tab is divided into distinct functional parts: a connection part connected to the electrode, a bent part with perpendicular extension, and a coupling part for connecting to the electrode lead. This segmentation allows each part to fulfill its specific function while optimizing the overall structure to prevent disconnection without excessive lengthening.
2Stability of the object's composition
If the electrode tab length is significantly increased to accommodate swelling, then the stability is improved, but the volume of the stationary object increases
Solution Approach 1:
The bent part extends in a direction substantially perpendicular to the stacking direction, utilizing unused spatial volume in the lateral dimension rather than increasing length in the stacking direction. This maintains battery compactness while providing sufficient tab length for stability during swelling.
Solution Approach 2:
The bent part is configured with a bent shape that provides flexibility and accommodation for swelling movements. The curved geometry allows the tab to absorb dimensional changes during battery operation without requiring excessive linear length, thereby maintaining compact battery volume.
Data Source
AI summary
A secondary battery comprises: an electrode assembly having electrodes, a separator interposed between the electrodes, and electrode tabs; an electrode lead coupled to the electrode tabs; and a pouch configured to accommodate the electrode assembly therein, wherein the electrode tabs comprise a connection part connected to the electrodes, a coupling part coupled to the electrode lead in a state of being combined into a mass, and a bent part provided between the connection part and the coupling part, and the bent part comprises a first bent surface connected to the coupling part and bent at a first-b angle, a second bent surface connected to the connection part and bent at a second-b angle, and a connection surface configured to connect the first bent surface to the second bent surface, wherein the first-b angle is greater than the second-b angle.