Stepped Electrode Assembly for Safer Secondary Battery Compression
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Solution Overview
Problem
Secondary batteries face challenges in enhancing safety and test reliability, particularly during thermal compression, where deformation of the outer electrode plate can lead to potential short circuits and errors in X-ray tests.
Innovation Solution
The design includes an outer electrode plate smaller than the inner and second electrode plates, with a Z-shaped separator to prevent deformation, ensuring the outer plate is securely supported and maintaining structural integrity during heat-press processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the outer electrode plate is made the same size as inner electrode plates, then the battery structure is simpler, but the outer electrode plate deforms during thermal compression causing short circuits and test errors
Solution Approach 1:
The patent applies local quality by making the outer electrode plate smaller than the inner electrode plates. This local dimensional difference creates a stepped configuration where the outer plate has different dimensions (smaller by 0.5-2mm in lateral and longitudinal lengths) compared to inner plates, preventing deformation during thermal compression while maintaining overall battery functionality.
Solution Approach 2:
The electrode plate system is segmented into different size categories: outer electrode plates with smaller dimensions and inner electrode plates with larger dimensions. This segmentation creates a hierarchical structure where outer plates are positioned at the periphery with reduced size, preventing them from deforming during compression tests while inner plates maintain full size for optimal electrochemical performance.
2Reliability
If the outer electrode plate is smaller than inner electrode plates, then deformation is prevented during thermal compression, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by specifying precise dimensional parameters for the outer electrode plate: lateral length difference of 0.5-2mm and longitudinal length difference of 0.5-2mm compared to inner electrode plates. These controlled parameter variations ensure the outer plate is smaller enough to prevent deformation during thermal compression while maintaining manufacturability within defined tolerances.
3Quantity of substance
If electrode plates are tightly packed to maximize energy density, then space utilization improves, but outer electrode plate deformation increases during heat-press processes
Solution Approach 1:
The patent applies asymmetry by creating an asymmetric electrode plate configuration where outer electrode plates have different (smaller) dimensions compared to inner electrode plates. This asymmetric stepped design allows the outer plates to be positioned at the periphery with reduced size, preventing deformation during heat-press processes while maximizing the utilization of internal space for higher energy density.
Data Source
AI summary
The present invention relates to a secondary battery capable of enhancing safety and test reliability. According to one embodiment, disclosed is a secondary battery comprising: an electrode assembly in which a first electrode plate and a second electrode plate are alternately stacked; and a case for accommodating the electrode assembly, wherein the first electrode plate includes an outer electrode plate located at the outermost part of the electrode assembly, and an inner electrode plate located inside the electrode assembly, and the outer electrode plate is smaller than the inner electrode plate and the second electrode plate.