Wound Secondary Battery Electrode Layout to Prevent Tab Protrusion Detachment
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Solution Overview
Problem
Secondary batteries face issues with electrode plate short-circuiting due to stress applied to protrusions on the winding outer side, leading to detachment and potential short-circuits.
Innovation Solution
The configuration of a secondary battery with a first electrode plate having a protrusion on the winding center side, reducing stress and preventing detachment, and ensuring the electrode plates are not short-circuited by orienting the protrusion towards the winding center.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a protrusion is formed on the electrode plate to improve connection, then connection strength is improved, but stress concentration occurs on the winding outer side causing detachment
Solution Approach 1:
The patent applies local quality by making the protrusion asymmetric in its positioning relative to the winding structure. The protrusion is specifically located on the winding center side rather than being symmetrically distributed, creating different local conditions on opposite sides of the electrode plate. This asymmetric local configuration ensures that the protrusion remains in a low-stress region while maintaining connection strength.
Solution Approach 2:
The patent employs asymmetry by deliberately positioning the protrusion only on one side (the winding center side) of the electrode plate rather than symmetrically on both sides. This asymmetric arrangement exploits the non-uniform stress distribution in the wound electrode assembly, placing the protrusion where it experiences minimal stress during winding and operation, thereby preventing detachment while maintaining electrical connection.
2Strength
If stress is applied to the protrusion on the winding outer side, then structural support is improved, but the protrusion detaches causing short-circuit
Solution Approach 1:
The patent applies preliminary anti-action by proactively positioning the protrusion on the winding center side before any stress-induced detachment can occur. This preemptive placement ensures that the protrusion is situated in a region that naturally experiences lower stress during winding and operation, preventing the harmful effect of detachment before it can happen. The asymmetric positioning serves as a preventive measure against the potential failure mode.
3Strength
If the protrusion height is increased to improve connection, then connection strength is improved, but stress concentration increases leading to detachment
Solution Approach 1:
The patent applies local quality by controlling the protrusion height relative to the local stress environment. The protrusion height is set to be smaller than the active material layer thickness, creating a localized feature that provides sufficient connection strength without creating excessive stress concentration. This controlled local geometry optimizes the balance between connection strength and stress management.
Data Source
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Figure 3(a)~4
Figure 5(a)~5(d)
AI summary
Provided is a highly reliable secondary battery. This secondary battery is provided with: a belt-like positive electrode plate having a plurality of positive electrode tabs; a belt-like negative electrode plate; a flat rolled electrode member which is obtained by rolling the positive electrode plate and the negative electrode plate with a separator (70) therebetween; and a positive electrode current collector which is connected in a state where the plurality of positive electrode tabs are stacked on one another, wherein the positive electrode plate has a positive electrode core body (4a) and a positive electrode active material layer (4b) formed on the positive electrode core bodies (4a). At one edge side of the positive electrode plate where the plurality of positive electrode tabs are provided, one surface of the positive electrode core body (4a) has formed thereon a first protrusion (4x) that protrudes from said surface of the positive electrode core body (4a) in the thickness direction of the positive electrode core body (4a), whereas the other surface of the positive electrode core body (4a) has no protrusion formed to protrude from said other surface of the positive electrode core body (4a) in the thickness direction of the positive electrode core body (4a). In the rolled electrode member the one surface of the positive electrode core body (4a) is disposed so as to face the roll center of the rolled electrode member.