Battery Electrode Assembly Insulation for Z-Shaped Plate Deformation
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Solution Overview
Problem
Secondary batteries face safety issues due to the deformation of the negative electrode plate into a Z-shape, leading to potential short circuits between the positive and negative electrode plates as the active material at the front end of the positive electrode plate comes into contact with the deformed negative electrode plate.
Innovation Solution
The electrode assembly incorporates specific non-coating portions and insulating tapes of varying sizes on both electrode plates to prevent short circuits, with longer insulating tapes on the outer surface to accommodate the expansion and contraction of the negative electrode plate, ensuring the cut ends of the electrode plates are covered by overlapping insulating tapes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the negative electrode plate is allowed to expand and contract freely during cycling, then the battery can maintain good electrochemical performance, but the front end deforms into a Z-shape causing short circuits between electrode plates
Solution Approach 1:
The patent introduces insulating tapes as intermediary elements between the positive and negative electrode plates. These tapes are specifically positioned at the front end non-coating portions where the negative electrode plate deforms during cycling. The insulating tapes act as mediators that prevent direct contact between the deformed negative electrode front end and the positive electrode plate, thereby eliminating the short circuit pathway while allowing the electrode plates to maintain their natural expansion and contraction behavior during electrochemical cycling.
Solution Approach 2:
The patent applies insulating tapes in advance to the non-coating portions at the front ends of the electrode plates before assembly and cycling begins. This preliminary protective measure ensures that when the negative electrode plate subsequently deforms into a Z-shape during normal operation, the deformation is already constrained by the pre-applied insulating tapes, preventing the harmful contact before it can occur.
2Reliability
If insulating tapes are applied to prevent short circuits, then safety is improved, but the device complexity increases due to additional components and assembly steps
Solution Approach 1:
The patent applies insulating tapes only to specific local areas - the non-coating portions at the front ends of the electrode plates - rather than covering the entire electrode surfaces. This localized application provides safety precisely where the Z-shaped deformation and short circuit risk occur, while minimizing the amount of additional material and assembly complexity required. The insulating tapes are positioned only where needed to prevent harmful contact, not as a universal coverage solution.
Data Source
AI summary
An electrode assembly for a secondary battery having improved safety is provided. According to the embodiments of the present disclosure, a front end and a rear end of a positive electrode plate may be insulated from each other to prevent a short circuit from occurring due to deformation of a front end of the negative electrode plate. A rear end of the negative electrode plate may be insulated to prevent a short circuit between the negative electrode plate and the positive electrode plate. An additional insulating tape may be provided on the rear end of the negative electrode plate to prevent defects due to Z-shaped deformation of the negative electrode plate from occurring.