Electrode Assembly Layout to Prevent Substrate Exposure
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Solution Overview
Problem
The exposure of the negative composite layer due to shrinkage of the negative electrode substrate in cylindrical rechargeable batteries leads to potential short circuits, compromising safety and stability.
Innovation Solution
The electrode assembly design includes a finishing tape that covers the ends of the substrate, with a circumferential length less than the main body, ensuring the substrate is positioned in multiple layers in exposed regions, preventing the composite layer from exposure during volume changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the finishing tape covers the entire circumference of the main body, then the substrate is fully protected from exposure, but the battery capacity and energy density are reduced due to excessive inactive material
Solution Approach 1:
The finishing tape is designed with a circumferential length that is smaller than the circumference of the main body, creating a localized coverage rather than complete circumferential coverage. This allows the substrate to be protected in critical regions while maintaining battery capacity in other areas, resolving the contradiction between protection and capacity.
Solution Approach 2:
The substrate is positioned to extend in the radial direction beyond the finishing tape, creating a multi-layer configuration. This dimensional arrangement ensures that even when the substrate shrinks, the inner layers remain protected while the outer extension provides additional safety margin without requiring complete circumferential coverage.
2Quantity of substance
If the finishing tape circumferential length is reduced to maintain battery capacity, then more substrate may be exposed during shrinkage, but this increases the risk of short circuit
Solution Approach 1:
The substrate is pre-positioned in a multi-layer configuration before the battery is assembled and before shrinkage occurs. This preliminary arrangement ensures that when shrinkage happens during charging-discharging cycles, the substrate layers are already positioned to protect the composite layer, preventing exposure and short circuits while maintaining optimized finishing tape dimensions.
Solution Approach 2:
The substrate is arranged in nested multiple layers within the battery structure, with each layer providing protective coverage. This nesting configuration allows the substrate to protect itself through its own layered structure, reducing the burden on the finishing tape while maintaining short circuit prevention.
3Reliability
If the substrate is positioned in multiple layers, then protection against exposure is improved, but the device complexity increases
Solution Approach 1:
The substrate is divided into multiple segments or layers along the radial direction, with each segment providing protective function. This segmentation allows the complex protection function to be distributed across simple, identical repeating units, reducing overall structural complexity while maintaining high reliability through redundancy.
Data Source
AI summary
An electrode assembly, includes: a main body including a first electrode and a second electrode stacked and wound with a separator in between, with a first substrate positioned at an outermost part of the main body; and a finishing tape attached to the main body to cover an end of the first substrate, wherein a circumferential length of the finishing tape is smaller than a circumference of the main body, and the first substrate is positioned in two layers over an entire exposed region of the main body which is not covered with the finishing tape.