Cylindrical Battery Tab Layout for Hollow-Core Gas Discharge
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Solution Overview
Problem
Cylindrical non-aqueous electrolyte secondary batteries face issues with blocked hollow parts during abnormal heat generation, preventing smooth gas discharge and potential buckling of electrode tabs due to cornered projections, which complicates assembly and safety.
Innovation Solution
A configuration where the negative electrode tab and reinforcement plates are wound without facing the positive electrode, extending for at least 0.75 turns, forming a group that surrounds the hollow part, ensuring smooth gas discharge and preventing tab projections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the negative electrode tab is wound for more than or equal to 0.75 turns without facing the positive electrode, then gas discharge path is secured and blockage is inhibited, but the two ends of the negative electrode tab project in a cornered form increasing the diameter of the wound electrode assembly
Solution Approach 1:
The negative electrode tab is divided into multiple segments arranged in a predetermined order (first tab, second tab, third tab, fourth tab) around the hollow part. This segmentation allows the tabs to be distributed evenly, preventing cornered projections while maintaining the gas discharge function. Each tab segment contributes to surrounding the hollow part without concentrating all tabs at one location.
Solution Approach 2:
The arrangement of negative electrode tabs follows an asymmetric predetermined order rather than uniform distribution. Specifically, the first and second tabs are arranged on one side of the hollow part while the third and fourth tabs are arranged on the opposite side, creating an asymmetric pattern that prevents cornered projections and maintains balanced diameter.
2Reliability
If the negative electrode tab is wound for more than or equal to 0.75 turns without facing the positive electrode, then gas discharge path is secured, but the electrode plate becomes buckled starting from cornered projecting portions
Solution Approach 1:
Dividing the negative electrode tab into multiple segments prevents concentration of stress at single projection points. The segmented tabs distribute mechanical stress evenly around the hollow part, preventing buckling initiation that would occur at cornered projections of a single continuous tab.
Solution Approach 2:
The reinforcement plates are strategically placed at specific locations where the negative electrode tabs are joined to the non-facing part. This local reinforcement provides structural support exactly where needed to prevent buckling, while maintaining flexibility elsewhere in the electrode assembly.
3Stability of the object's composition
If a non-facing part is provided extending for more than or equal to two full turns, then deformation at the winding-start side is suppressed, but the hollow part may become blocked during abnormal heat generation
Solution Approach 1:
The non-facing part is segmented into multiple negative electrode tabs distributed around the hollow part rather than forming a continuous long extension. This segmentation maintains structural stability at the winding-start side while creating open spaces between tabs that prevent blockage of the hollow part during thermal runaway.
Solution Approach 2:
The negative electrode tabs are pre-arranged in a predetermined order around the hollow part before winding completion. This preliminary arrangement ensures that the tabs surround the hollow part in a controlled manner, maintaining stability while preserving gas discharge pathways from the outset.
Data Source
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AI summary
A non-aqueous electrolyte secondary battery according to the present invention comprises: an electrode body (14) in which a long positive electrode (11) and a long negative electrode (12) are wound with a separator therebetween; a non-aqueous electrolyte; and an exterior can in which the electrode body and the non-aqueous electrolyte are housed. The negative electrode has: a non-facing part (60) which is on the winding start side from a facing part (59) that faces the winding inner side of a starting end part (11a) of the positive electrode in the winding direction and which is wound so as not to face the positive electrode; and a tab reinforcement plate group (70) which is joined to the non-facing part. The tab reinforcement plate group has a negative electrode tab (21) and reinforcement plates (71, 72). The negative electrode tab and at least one reinforcement plate are disposed so as to be arranged in a prescribed order for a total of 0.75 turns or more from a winding start end of the tab reinforcement plate group, which is an origin of winding, toward the winding end side.