Electrode Assembly Edge Insulation Against Separator Shrinkage
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Solution Overview
Problem
Secondary batteries face safety risks due to separator damage leading to short circuits between positive and negative electrode plates, which can ignite, especially in high temperature environments, and manufacturing issues like burrs on electrode plates can further increase this risk.
Innovation Solution
The electrode assembly incorporates insulating tapes at non-coated portions of the electrode plates, including first and second insulating tapes on the positive electrode plate and a third insulating tape on the negative electrode plate, to prevent short circuits by insulating the leading and trailing edges, with specific configurations to cover and overlap active material layers and tab cover tapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the separator is used without additional protective measures, then the battery structure remains simple, but the separator may be damaged in high temperature environments leading to short circuits
Solution Approach 1:
An insulating tape is introduced as an intermediary component between the electrode plate and the separator. This tape specifically protects the non-coated portion of the electrode plate at the leading and trailing edges, preventing direct contact between the electrode plate and separator that would cause short circuits. The insulating tape acts as a mediator that eliminates the harmful interaction while maintaining the functional relationship between the electrode and separator.
Solution Approach 2:
The insulating tape is attached to the electrode plate before the electrode assembly is completed and before any potential separator damage can occur. This preliminary protective measure ensures that when the separator shrinks or gets damaged in high temperature environments, the non-coated portions of the electrode plate are already protected, preventing short circuits before they can happen.
2Reliability
If the non-coated portion of the electrode plate is left exposed, then the manufacturing process remains simple, but the adhesion to the separator is weak and shrinkage increases in high temperature environments
Solution Approach 1:
The insulating tape serves as an intermediary that attaches to the non-coated portion of the electrode plate, providing the necessary adhesion and structural support. This tape prevents the separator from shrinking away from the electrode plate edges while maintaining ease of manufacture by using a simple attachment process rather than complex electrode plate modifications.
3Reliability
If burrs are not removed from the cutting surface of the electrode plate, then the manufacturing process remains fast, but there is a high risk of damage to the separator
Solution Approach 1:
The insulating tape is attached to the electrode plate before assembly, creating a protective cushion that prevents burrs from damaging the separator. This beforehand cushioning approach eliminates the need for additional burr removal steps, maintaining high manufacturing productivity while ensuring separator protection.
Solution Approach 2:
The insulating tape acts as an intermediary barrier between the potentially defective electrode plate surface (with burrs) and the separator. This mediator prevents direct contact that would cause separator damage, allowing the electrode plate to be manufactured without stringent burr removal requirements.
4Reliability
If no insulating measures are taken at the edges, then the device structure remains simple, but short circuit paths can form when the separator is damaged
Solution Approach 1:
The insulating tape is positioned as an intermediary layer between the electrode plate and separator at the critical leading and trailing edges. This mediator blocks potential short circuit paths that would form if the separator is damaged, while adding minimal structural complexity compared to alternative comprehensive insulating solutions.
Solution Approach 2:
Instead of applying insulating measures uniformly across the entire electrode plate, the insulating tape is applied locally only at the leading and trailing edges where non-coated portions exist. This local quality approach prevents short circuits at the most vulnerable points without unnecessarily complicating the overall device structure.
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
Disclosed is an electrode assembly for secondary batteries, the electrode assembly including a first electrode plate having side A and side B on which a non-coated portion is formed at each of a first leading edge and a first trailing edge of both side-A and side-B and a positive electrode tab, a second electrode plate having side A and side B on which a non-coated portion is formed at each of a first leading edge and a first trailing edge of both side-A and side-B and a negative electrode tab, a separator interposed between the first electrode plate and the second electrode plate, a tab cover tape attached to each of the positive electrode tab and the negative electrode tab, a first insulating tape attached to the non-coated portion, and a second insulating tape attached to the non-coated portion.