Electrode Assembly Insulation Layers Prevent Short Circuits
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Solution Overview
Problem
Cylindrical secondary batteries face issues with internal resistance and a high risk of short circuits due to electrode meandering, which can lead to heat generation or explosion.
Innovation Solution
An electrode assembly structure with uncoated portions and insulation layers extending from the boundary between coated and uncoated regions, featuring notching valleys and segments to prevent electrode contact, along with a manufacturing method that includes laser irradiation and segment bending.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a jelly roll type electrode assembly is used to maximize current collection efficiency, then current collection efficiency is improved, but the risk of short circuit increases due to electrode meandering
Solution Approach 1:
An insulating member is introduced as an intermediary between the positive and negative electrodes. This insulating member includes an insulating layer formed on a support structure, creating a physical barrier that prevents electrical contact between electrodes while allowing the jelly roll configuration to maintain its current collection efficiency
Solution Approach 2:
The insulating member is designed with a segmented structure that includes a support divided into multiple regions, with insulating layers positioned at specific locations where electrode contact is most likely to occur. This segmentation allows targeted protection without compromising overall current collection
2Reliability
If insulation layers are added to prevent electrode contact, then short circuit risk is reduced, but internal resistance increases
Solution Approach 1:
The insulating layer is applied selectively only at critical locations where electrode meandering and contact are most likely to occur, rather than covering the entire electrode surface. This localized approach provides necessary insulation while minimizing the total insulating material present, thereby reducing the impact on internal resistance
Solution Approach 2:
The insulating member provides just enough insulation coverage to prevent short circuits under normal operating conditions and expected electrode movement, without excessive insulation that would significantly increase internal resistance. The support structure is designed with optimal thickness and material properties to balance insulation and conductivity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Reduces internal resistance for rapid charging and discharging while effectively preventing short circuits, enhancing battery safety.
Implementation Method 1
a plurality of uncoated portion notching valleys formed along a winding direction of the electrode assembly
Implementation Method 2
a first insulation layer and a second insulation layer extending by a predetermined length from a region including a boundary between the coated portion and the uncoated portion are provided
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Disclosed is an electrode assembly having a structure in which a stack including a first electrode, a second electrode, and a separator interposed therebetween is wound. The first electrode and the second electrode have an uncoated portion provided at a long side end and not coated with an active material and a coated portion coated with the active material, respectively. On a first surface of the first electrode and a second surface opposite to the first surface, a first insulation layer and a second insulation layer extending by a predetermined length from a region including a boundary between the coated portion and the uncoated portion toward an end of the uncoated portion are provided, respectively.