Cylindrical Battery Tab Insulation Structure for Crack Prevention
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Solution Overview
Problem
Cylindrical secondary batteries may experience cracks or ruptures along the boundary area of the electrode tab due to stress caused by pressure applied to the jelly roll electrode assembly and the thickness of the electrode tab.
Innovation Solution
A secondary battery design that includes an insulation tape with the same thickness as the electrode tab attached to the electrode uncoated portion around the electrode tab, along with a step compensation unit on the upper surface of the insulation tape, to compensate for pressure and reduce the risk of cracks or ruptures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an electrode tab with certain thickness is used in a cylindrical secondary battery, then the electrical connection is ensured, but stress caused by pressure applied to the jelly roll electrode assembly causes cracks to occur along the boundary area of the electrode tab
Solution Approach 1:
The patent applies a protective layer to the boundary area of the electrode tab before the battery is subjected to pressure during operation. This preliminary protective measure prevents cracks from forming in the first place by reinforcing the vulnerable boundary region where the electrode tab meets the current collector, thereby resolving the contradiction between maintaining electrical connection and preventing stress-induced cracks.
Solution Approach 2:
The patent introduces a cushioning layer or structure at the boundary area of the electrode tab that absorbs and distributes the stress caused by pressure applied to the jelly roll electrode assembly. This beforehand cushioning prevents the concentration of stress that would otherwise lead to cracks, while still allowing the electrode tab to maintain its electrical function.
2Stability of the object's composition
If pressure is applied to the jelly roll electrode assembly during battery operation, then the battery maintains its cylindrical shape and structural stability, but stress causes cracks to occur along the boundary area of the electrode tab
Solution Approach 1:
The patent applies a protective layer specifically to the boundary area of the electrode tab rather than uniformly across the entire electrode structure. This local quality approach reinforces the vulnerable boundary region where cracks are most likely to occur while maintaining the overall cylindrical shape stability through controlled pressure application.
Solution Approach 2:
The patent uses a composite structure consisting of the electrode tab material combined with a protective layer material at the boundary area. This composite construction provides both the electrical conductivity needed for battery operation and the enhanced mechanical strength required to resist cracks under pressure, while maintaining the cylindrical shape.
Data Source
AI summary
A secondary battery includes: a first electrode plate including a first substrate having a first active material coated portion coated with a first active material and a first electrode uncoated portion not coated with the first active material; a second electrode plate including on a second substrate having a second active material coated portion coated with a second active material and a second electrode uncoated portion not coated with the second active material; a separator between the first electrode plate and the second electrode plate; an electrode tab connected to one of the first electrode uncoated portion and the second electrode uncoated portion; an insulation tape on the first electrode uncoated portion or the second electrode uncoated portion and covering the electrode tab; and a step compensation unit on a region of an upper surface of the insulation tape excluding a region corresponding to the electrode tab.