Lithium Battery Electrode Insulation for Short Circuit Prevention
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Solution Overview
Problem
Lithium secondary batteries are prone to internal short circuits due to contact between non-coating portions and active material layers, especially when the separator is damaged or shrinks, leading to potential ignition or explosion risks.
Innovation Solution
An electrode assembly is designed with insulating members attached to the non-coating portions of the electrode plates, particularly on the outer periphery, to prevent contact with the active material layers, and lamination tapes are used to cover the non-coating portions on the inner periphery, ensuring insulation and preventing short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If insulating tape is attached only to electrode tab-fixed regions, then manufacturing process is simple, but internal short circuit may occur due to non-coating portion contact when separator is damaged
Solution Approach 1:
The patent applies insulating tape to non-coating portions before any damage or short circuit risk occurs. By pre-insulating these vulnerable areas where non-coating portions are exposed, the structure is prepared in advance to prevent short circuits even if separator damage occurs during battery operation.
Solution Approach 2:
The insulating tape application is segmented into specific regions: electrode tab-fixed regions and non-coating portions. This segmentation allows targeted insulation where needed (at non-coating portions prone to contact) while maintaining manufacturing efficiency by not requiring complete coverage of entire electrode surfaces.
2Device complexity
If non-coating portions are left exposed without additional insulation, then device structure is simple, but short circuit risk increases due to contact with active material layer
Solution Approach 1:
The patent applies insulating tape specifically to non-coating portions where the risk of short circuit exists, rather than uniformly insulating entire electrodes. This localized insulation approach addresses the specific harmful contact risk at non-coating portions while maintaining overall structural simplicity and avoiding unnecessary complexity elsewhere.
Solution Approach 2:
The insulating tape acts as an intermediary material between the non-coating portion and the active material layer. This intermediate insulating layer prevents direct contact and potential short circuits between oppositely charged electrode regions, eliminating the harmful effect without requiring fundamental changes to electrode structure.
3Device complexity
If separator alone provides insulation, then battery structure is simple, but insulation fails when separator shrinks or is damaged by heat or impact
Solution Approach 1:
The insulating tape is applied to non-coating portions as a pre-cautionary measure before any separator damage or shrinkage occurs. This additional insulating layer serves as a backup protective barrier that remains effective even when the separator's insulating function is compromised by thermal shrinkage, mechanical impact, or other stressors.
Solution Approach 2:
The insulating tape provides a flexible thin film layer that adheres to non-coating portions and maintains insulation functionality independently of separator condition. This thin film insulation complements the separator by providing an additional barrier that is not subject to the same shrinkage or damage mechanisms.
Data Source
Figure 1
Figure 2A
Figure 2B~2C
AI summary
An electrode assembly and a lithium secondary battery comprising the same are disclosed. Specifically, the present invention provides an electrode assembly which is capable of preventing the occurrence of a short circuit between a non-coating portion of an electrode plate and an active material layer of an electrode plate having an opposite polarity when damage or shrinkage of a separator takes place, through the attachment of an insulating tape to either or both sides of the non-coating portion of an electrode plate without attachment of an electrode tab. Therefore, an internal short circuit of the battery can be prevented by application of the electrode assembly of the present invention to a variety of lithium secondary batteries including pouch-type, polygonal and cylindrical batteries.