Electrode Assembly Burr Orientation and Insulation for Short Circuit Prevention
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Solution Overview
Problem
The challenge in suppressing short circuits between cathode and anode electrodes due to burrs created during the punching process, where the burr height is difficult to control and can lead to contact between facing electrodes, even with insulation layers, due to variations in thickness and clearance settings during manufacturing.
Innovation Solution
The electrode assembly includes a cathode and an anode with insulation layers covering the active material layers, positioned such that the burrs from the punching process do not face each other at the edges, ensuring they do not contact, thereby preventing short circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If punching is used to form electrodes into predetermined shapes, then productivity is improved, but burrs are created on the cut section which may penetrate the separator and cause short circuits
Solution Approach 1:
An insulation layer is formed on the electrode surface before the punching process. This preliminary protective layer prevents burrs generated during punching from penetrating the separator and causing short circuits, thus maintaining reliability while preserving the productivity benefits of punching.
Solution Approach 2:
The insulation layer acts as an intermediary between the burr (harmful factor) and the separator (critical component). It intercepts and neutralizes the harmful effect of burrs, preventing them from reaching and penetrating the separator, thereby resolving the contradiction between productive punching and reliable short circuit prevention.
2Reliability
If the clearance between die and punch is reduced to suppress burr height, then short circuit risk is reduced, but manufacturing complexity increases
Solution Approach 1:
Instead of changing the clearance parameter (which increases device complexity), the invention changes the electrode surface parameter by adding an insulation layer. This alternative parameter change achieves burr height suppression without complicating the punching device, resolving the contradiction between reliability and manufacturing complexity.
3Ease of manufacture
If polyolefin separator is used for cost effectiveness, then manufacturing cost is reduced, but separator melts at high temperatures causing short circuits
Solution Approach 1:
An insulation layer is formed on the electrode surface before assembly, serving as a preliminary thermal barrier. This layer prevents direct contact between electrodes at high temperatures, compensating for the polyolefin separator's melting limitation and maintaining reliability while preserving cost effectiveness.
Solution Approach 2:
The insulation layer acts as a thermal intermediary between the electrodes, preventing direct thermal contact that would cause short circuits when the polyolefin separator melts. This intermediary preserves the benefits of using inexpensive polyolefin separators while eliminating their thermal stability drawback.
Data Source
AI summary
A purpose of the present invention is to provide an electrode assembly and a manufacturing method therefor that can favorably suppress a short circuit that is due to a burr created by punching. At least one of the cathode 11 and the anode 12 of the electrode assembly of the present invention is covered with an insulating layer. The cathode 11 and the anode 12 are oriented such that the burr 11b of the cathode 11 and the burr 12b of the anode 12 of the opposing cathode 11 and the opposing anode 12 close to at least the outer peripheral edge of the cathode 11 and the outer peripheral edge of the anode 12 do not face each other 12 are opposed to each other.