Rechargeable Battery Short-Circuit Protrusion Surface Roughness
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Solution Overview
Problem
Rechargeable batteries face the risk of explosion or fire due to increased internal pressure from abnormal reactions, which existing safety measures do not adequately address by reducing contact resistance during short-circuits.
Innovation Solution
A rechargeable battery design featuring a second terminal with a short-circuit protrusion having increased surface roughness, which reduces contact resistance when a short-circuit occurs, thereby preventing explosions or fires by facilitating efficient electrical coupling between electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a smooth surface is used for the terminal, then manufacturing is easier, but contact resistance increases during short-circuit
Solution Approach 1:
The patent applies local quality by creating micro-sized protrusions only on the short-circuit protrusion surface rather than the entire terminal. This localized surface treatment increases contact resistance reliability at the critical contact point while minimizing manufacturing complexity. The rough surface is applied selectively where contact occurs, leaving other areas smooth and easy to manufacture.
Solution Approach 2:
The patent changes the surface parameter from smooth to rough by introducing micro-sized protrusions with specific height ranges (0.5-100 μm). This parameter change increases the contact area and reduces contact resistance during short-circuit events. The controlled modification of surface roughness parameters directly addresses the reliability issue without fundamentally altering the manufacturing process.
2Reliability
If a large contact area is created between terminals, then contact resistance decreases, but the device complexity increases
Solution Approach 1:
The patent creates a large contact area through micro-sized protrusions localized on the short-circuit protrusion surface. This approach increases the effective contact area and reduces contact resistance without adding overall device complexity. The complex surface structure is confined to a small localized region, keeping the rest of the device simple.
Solution Approach 2:
The patent transitions from a two-dimensional smooth surface to a three-dimensional micro-protrusion surface. By adding vertical dimensionality with protrusions of 0.5-100 μm height, the contact area increases significantly without expanding the horizontal footprint. This dimensional change reduces contact resistance while maintaining compact device dimensions and avoiding increased complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The increased surface roughness of the short-circuit protrusion on the second terminal reduces contact resistance, allowing for effective electrical coupling and potentially preventing short-circuit-related explosions or fires by increasing the contact area and ease of melting the short-circuit member.
Implementation Method 1
a surface roughness of the short-circuit protrusion is greater than that of the cap plate
Implementation Method 2
a short-circuit member at the cap plate, corresponding to the short-circuit opening, and configured to deform to electrically couple the first and second electrodes
Implementation Method 3
contact resistance is reduced when the short-circuit member contacts the short-circuit protrusion
Data Source
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AI summary
A rechargeable battery includes an electrode assembly including first and second electrodes; a case accommodating the electrode assembly; a cap plate having a short-circuit opening; a first terminal coupled to the first electrode; a second terminal coupled to the second electrode; and a short-circuit member at the cap plate, corresponding to the short-circuit opening, and configured to deform to electrically couple the first and second electrodes; and a short-circuit protrusion at the second terminal and configured to contact the short-circuit member, wherein a surface roughness of the short-circuit protrusion is greater than that of the cap plate.