Li-Ion Electrode Assembly Structure for Deformation Control
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Solution Overview
Problem
Lithium-ion secondary batteries face issues with deformation of the electrode assembly, which can lead to electrical short circuits.
Innovation Solution
The introduction of an anti-deformation portion attached to the positive electrode leading end uncoated portion, with a length of about 1/3 to 2/3 of the electrode assembly's circumference, and additional separators between the extension portion and negative electrode plate, along with a specific cap assembly design to prevent deformation and short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the electrode assembly is made compact to increase energy density, then the specific energy is improved, but the core deformation occurs leading to electrical short circuits
Solution Approach 1:
An anti-deformation portion is introduced as an intermediary component between the positive electrode leading end uncoated portion and the core. This anti-deformation portion prevents core deformation that would otherwise lead to electrical short circuits, thereby maintaining reliability while preserving the compact design for high energy density.
Solution Approach 2:
The anti-deformation portion is attached in advance to the positive electrode leading end uncoated portion before the battery operation begins. This preliminary action prevents core deformation from occurring in the first place, ensuring that the electrode assembly maintains its structural integrity throughout the battery's lifecycle without electrical short circuits.
2Reliability
If the anti-deformation portion length is increased to better prevent core deformation, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The length of the anti-deformation portion is optimized to a specific parameter range (1/3 to 2/3 of the circumferential length of the core). This parameter optimization ensures sufficient core deformation prevention while avoiding excessive complexity. The specific length range provides the necessary structural support without over-engineering the solution.
3Reliability
If additional separators are added between the extension portion and negative electrode plate to prevent short circuits, then the electrical short circuit prevention is improved, but the device complexity increases
Solution Approach 1:
Additional separators are placed specifically between the extension portion of the positive electrode leading end uncoated portion and the negative electrode plate, only where needed to prevent electrical short circuits. This localized approach provides enhanced safety precisely at the vulnerable core region without adding unnecessary complexity to the entire battery structure.
Data Source
Figure 1A
Figure 1B
Figure 2~3A
AI summary
A secondary battery includes an electrode assembly including a negative electrode plate including a negative electrode leading end uncoated portion, a positive electrode plate including a positive electrode leading end uncoated portion, and an anti-deformation portion attached to the positive electrode leading end uncoated portion, an end of the positive electrode leading end uncoated portion and an end of the anti-deformation portion being located ahead of an end of the negative electrode leading end uncoated portion, a case accommodating the electrode assembly, and electrically coupled to the negative electrode plate, and a cap assembly sealing the case.