Secondary Battery Electrode Asymmetry for Volume Control
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Solution Overview
Problem
The existing secondary battery designs, particularly the laminated type, face issues with increased volume and deformation due to insulating members used to prevent short-circuiting, which affect energy density and electric characteristics.
Innovation Solution
The design alternately stacks positive and negative electrodes via separators, with the insulating member positioned differently on the front and rear surfaces of the collectors to avoid thickness variations, allowing for uniform pressure application and maintaining high energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If insulating members are formed to cover boundary portions between coated and uncoated portions of electrodes, then short-circuiting prevention is improved, but battery assembly volume increases and energy density decreases
Solution Approach 1:
The patent applies asymmetry by positioning boundary portions at different locations on the front and rear surfaces of each electrode. This asymmetric arrangement prevents insulating members from overlapping when electrodes are stacked, thereby reducing the overall battery assembly volume while maintaining short-circuiting prevention functionality.
Solution Approach 2:
The patent utilizes the planar dimension by strategically positioning boundary portions at different lateral locations on front and rear surfaces. This dimensional arrangement ensures that insulating members are distributed across different planar positions, preventing vertical overlap and reducing volume accumulation in the stacking direction.
2Ease of manufacture
If insulating members are positioned at the same location on front and rear surfaces, then short-circuiting prevention is simplified, but battery assembly deformation occurs and electric characteristics vary
Solution Approach 1:
By making the positions of boundary portions asymmetric between front and rear surfaces, the patent prevents insulating members from aligning vertically during stacking. This eliminates localized thickness variations and deformation while maintaining manufacturing simplicity through the consistent application of the asymmetric design rule.
Data Source
Figure 1~2
Figure 3~4
Figure 5a~5b
AI summary
Secondary battery includes a battery assembly configured by alternately stacking positive electrodes 1 and negative electrodes 6 via separators 20, in which the positive electrode and the negative electrode respectively include collectors 3 and 8, and active materials 2 and 7 applied on the collectors. On each surface of the collector, a coated portion coated with the active material and an uncoated portion not coated with any active material are provided. In one or both of the positive electrode and the negative electrode, boundary portion 4a between the coated portion and the uncoated portion on the front surface of the collector, is positioned planarly away from boundary portion 4b between the coated portion and the uncoated portion on the rear surface of the collector.