Wound Battery Electrode Tab Layout to Prevent Separator Piercing
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Solution Overview
Problem
Existing batteries with high energy density face increased safety risks due to potential short-circuits caused by current collecting tabs piercing separators under external impact or stress, leading to manufacturing defects and reduced yield.
Innovation Solution
The battery design includes a current collecting tab connected to one end of the electrode plate within a range not exceeding its center, with a dummy tab overlapping to balance thickness and rigidity, reducing winding deviation and internal short-circuits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the current collecting tab is shortened to exclude it from the center of the electrode group, then safety is improved by preventing piercing of the separator, but non-uniformity of thickness and rigidity between both sides of the electrode plate increases, causing winding deviation
Solution Approach 1:
A dummy tab is provided that copies the structural characteristics of the current collecting tab but does not extend beyond the center of the electrode plate. This dummy tab replicates the thickness and rigidity balancing function of the current collecting tab on the opposite side, allowing the current collecting tab to be shortened for safety without causing winding deviation. The dummy tab serves as a structural counterpart that maintains symmetry in the electrode plate assembly.
2Use of energy by moving object
If high energy density is achieved, then battery performance is improved, but the risk of internal short-circuit increases due to deformation under external impact or stress
Solution Approach 1:
The current collecting tab is extracted or shortened so that it does not extend beyond the center of the electrode plate in the width direction. This extraction removes the dangerous portion of the tab that could pierce the separator under external impact or stress, while the dummy tab provides structural balance. This allows high energy density batteries to maintain improved safety by preventing tab penetration into the separator.
3Reliability
If the current collecting tab is shortened to improve safety, then the risk of separator piercing is reduced, but the rigidity balance between both sides of the electrode plate is disrupted, increasing winding deviation
Solution Approach 1:
The dummy tab is designed to copy the structural characteristics of the current collecting tab, providing equivalent rigidity and thickness balance on the opposite side of the electrode plate. This copying approach restores the rigidity uniformity that would otherwise be disrupted by shortening the current collecting tab, while still maintaining the safety benefit of preventing separator piercing.
Data Source
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AI summary
A battery according to an embodiment comprises: an electrode group in which a band-like positive electrode plate (11) and a band-like negative electrode plate are wound with a separator therebetween; an electrolyte; and an outer can. The positive electrode plate (11), in which a positive electrode mix layer (31) is formed on a band-like positive electrode core (30), comprises: a positive electrode tab (20) which is connected to an area on one end side of the positive electrode core (30) and not extending beyond the center in the width direction of the positive electrode plate (11); and a dummy tab (37) which is connected to an area on the other end side of the positive electrode core (30) and not extending beyond the center in the width direction of the positive electrode plate (11). When the positive electrode plate (11) is viewed in the width direction, the dummy tab (37) is disposed to overlap at least a part of the positive electrode tab (20).