Pouch Battery Inner Reinforcement Against Electrolyte-Induced Deformation
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Solution Overview
Problem
Pouch-type secondary batteries experience shape deformation due to negative pressure caused by excess electrolyte impregnation during charging and discharging, leading to issues with pack tape lifting and exterior quality problems.
Innovation Solution
A deformation preventing portion is integrated into the inner side of the pouch case, formed using curable tape, coating agents, or spraying methods, with shapes such as straight bars, semicircles, or spots, arranged to maintain the pouch's original shape by preventing inward concave deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the pouch is formed to be larger than the electrode assembly to improve insertion performance, then electrode assembly insertion performance is improved, but shape deformation of the pouch occurs due to negative pressure from excess electrolyte impregnation
Solution Approach 1:
A deformation preventing portion is formed on the inner side of the pouch case before electrode assembly insertion. This preliminary structural modification prevents the pouch from deforming during subsequent charging and discharging cycles by providing mechanical support against the negative pressure generated by electrolyte impregnation in the empty space.
Solution Approach 2:
The deformation preventing portion is strategically placed only in specific regions of the pouch case where deformation is most likely to occur during charging and discharging. This localized reinforcement maintains the overall flexibility of the pouch while providing targeted support to prevent shape deformation in critical areas.
2Shape
If pack tape is attached to correct deformed pouch shape, then exterior quality is temporarily improved, but pack tape lifting occurs due to ongoing deformation
Solution Approach 1:
The deformation preventing portion is installed before the pouch is sealed and before any pack tape attachment. By preventing deformation at the source through this preliminary structural modification, the need for corrective pack tape attachment is eliminated, and adhesion reliability issues are prevented before they can occur.
3Ease of operation
If excess electrolyte is used to fill empty space in the pouch, then electrode assembly insertion is facilitated, but negative pressure forms during charging and discharging causing deformation
Solution Approach 1:
The deformation preventing portion is prepared in advance on the pouch case before electrolyte filling. This preliminary structural reinforcement allows the pouch to accommodate excess electrolyte for easy insertion while resisting the negative pressure that develops during operation, preventing the electrolyte volume from causing deformation.
Solution Approach 2:
The deformation preventing portion acts as a structural counterbalance to the negative pressure generated by electrolyte impregnation in the empty space. This rigid or semi-rigid structure provides opposing force to counteract the collapsing pressure, maintaining pouch shape stability despite the presence of excess electrolyte.
Data Source
AI summary
Embodiments of the present disclosure relate to a secondary battery having a structure capable of reducing shape deformation of a pouch. A secondary battery includes: an electrode assembly; a pouch case accommodating the electrode assembly together with an electrolyte; and a deformation preventing portion at an inner side facing a terminal formation portion of the pouch case.