Pouch Cell Sealing Structure to Restrain Electrode Assembly Movement
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Solution Overview
Problem
Existing secondary batteries face issues with the movement of the electrode assembly within the pouch due to impacts, leading to potential short circuits and damage.
Innovation Solution
The secondary battery design incorporates a fixed sealing portion and an extended sealing portion to secure the electrode assembly, using insulating tape to prevent electrical contact and additional sealing portions to minimize movement, ensuring the pouch is securely sealed without overlapping the electrode or lead tabs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If only a fixed sealing portion is used to seal the pouch, then the manufacturing process is simple, but the electrode assembly can move due to impacts
Solution Approach 1:
The sealing portion is divided into two functional segments: a fixed sealing portion that seals the pouch opening and an extended sealing portion that extends toward the electrode assembly to prevent movement. This segmentation allows each portion to perform its specific function independently, improving reliability without excessive complexity.
Solution Approach 2:
The sealing structure extends in the width direction from the fixed sealing portion toward the electrode assembly, adding a spatial dimension to the sealing function. This extended sealing portion creates additional constraint in the horizontal plane, preventing electrode assembly movement while maintaining manufacturing feasibility.
2Reliability
If the extended sealing portion extends far toward the electrode assembly, then movement is restrained, but the risk of overlapping with electrode tabs increases
Solution Approach 1:
An insulating tape is introduced as an intermediary element between the extended sealing portion and the electrode assembly. This insulating tape prevents direct contact between the sealing portion and conductive components, eliminating the short circuit risk while allowing the extended sealing portion to maintain its movement-restraining function.
Solution Approach 2:
The extended sealing portion is designed to extend partially toward the electrode assembly but not fully contact it, stopping at a controlled distance. This partial extension provides sufficient movement constraint while maintaining safety margins to prevent harmful contact with electrode tabs.
3Reliability
If insulating tape is added between the lead tab and pouch, then electrical insulation is improved, but the device complexity increases
Solution Approach 1:
The insulating tape serves multiple functions simultaneously: it provides electrical insulation between the lead tab and pouch, acts as a spacer to maintain proper positioning, and contributes to the overall sealing structure. This multi-functionality justifies the additional component by delivering multiple benefits from a single element.
Data Source
AI summary
Disclosed is a secondary battery capable of restraining movement of an electrode assembly located in a pouch. The secondary battery includes an electrode assembly including a positive electrode plate, a negative electrode plate, and a separator disposed between the positive electrode plate and the negative electrode plate, a pouch accommodating the electrode assembly, a lead tab connected to an electrode tab extending from the electrode assembly, the lead tab extending outwardly of the pouch, a fixed sealing portion configured to seal an edge of the pouch, and an extended sealing portion located between the fixed sealing portion and the electrode assembly to seal a portion of the pouch at which the electrode tab and the lead tab are not located.