Wound Secondary Battery Separator Structure for Electrode Alignment
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Solution Overview
Problem
Current secondary batteries face challenges in achieving higher reliability and preventing internal short circuits, particularly due to local stresses and misalignment of electrodes during charging and discharging, which can lead to reduced performance and capacity.
Innovation Solution
The secondary battery employs a tabless structure with a stacked separator configuration where three or more bases are stacked, and the inner winding side edges of the positive and negative electrodes overlap, enhancing the separator's strength and preventing misalignment, thereby reducing the risk of internal short circuits and improving safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional battery structure is used, then manufacturing is simpler, but internal short circuits occur due to electrode misalignment and local stresses
Solution Approach 1:
The separator is divided into multiple bases (first base, second base, third base, etc.) that are stacked together. Each base provides structural support and the stacked configuration creates an integrated separator structure with enhanced mechanical strength and alignment stability, preventing electrode misalignment and internal short circuits during battery operation
Solution Approach 2:
The separator structure combines multiple bases into a composite configuration where the stacked bases work together as a unified component. This composite structure provides both the separation function and the mechanical reinforcement needed to maintain electrode alignment under stress, solving the reliability issue without requiring fundamentally new materials
2Stability of the object's composition
If electrode alignment is not optimized, then manufacturing is easier, but local stresses cause misalignment during charging and discharging
Solution Approach 1:
The multiple bases are pre-stacked in a predetermined configuration before the electrodes are assembled. This preliminary structuring of the separator ensures that the electrodes maintain proper alignment during subsequent assembly and during charging/discharging cycles, as the stacked bases provide built-in structural guidance and support
Solution Approach 2:
The stacked base structure acts as a cushioning mechanism that absorbs and distributes local stresses before they can cause electrode misalignment. The multiple layers of bases provide mechanical compliance that protects the electrode alignment during battery operation, preventing the harmful effects of stress concentration
3Volume of moving object
If a compact battery design is implemented, then space utilization improves, but battery capacity may be reduced
Solution Approach 1:
The stacked base structure changes the physical parameters of the separator by creating a more space-efficient configuration. The vertical stacking of bases reduces the horizontal space required while maintaining the necessary separation distance, allowing for better space utilization in the battery design without compromising capacity
Data Source
AI summary
A secondary battery includes an electrode wound body including a stacked structure wound around a central axis extending in a first direction. The stacked structure includes a positive electrode and a negative electrode that are stacked with a separator interposed therebetween. The separator includes a stacked part in which three or more bases are stacked. At least two of the three or more bases are folded back in a center region of the electrode wound body. The center region of the electrode wound body is a region located on an inner winding side relative to an inner winding side end part of a negative electrode current collector. In the electrode wound body, an inner winding side edge of the positive electrode, the negative electrode, and the stacked part overlap each other.