Battery Electrode Tab Cutout Geometry to Suppress Cracking
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Solution Overview
Problem
Strong compression of the active material layer in battery electrodes leads to cracking in the root of the tab portion of the electrode current collector and its vicinity, which is exacerbated by the expansion and contraction during battery charging and discharging.
Innovation Solution
A battery electrode design featuring a cutout from the root of the tab portion to the based portion, defined by a first curve with a first arc and a second curve with smaller curvature or a straight line, to alleviate stress and prevent cracking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the active material layer is compressed with a strong force to increase packing density, then the volumetric energy density of the battery is enhanced, but cracking occurs in the root of the tab portion of the electrode current collector and its vicinity
Solution Approach 1:
The electrode current collector is segmented by forming cutouts in the root of the tab portion and its vicinity. These cutouts divide the continuous structure into sections that can independently accommodate expansion and contraction of the active material layer during compression, preventing stress concentration and cracking while maintaining high packing density.
Solution Approach 2:
The cutouts are strategically positioned only in the root of the tab portion and its vicinity, where stress concentration and cracking are most likely to occur. The local structure is modified in this critical region while the rest of the electrode current collector maintains its original continuous structure, providing targeted stress relief where needed.
2Quantity of substance
If the active material layer is strongly compressed to increase volumetric energy density, then the packing density increases, but the electrode current collector undergoes expansion and contraction during charging and discharging causing cracking
Solution Approach 1:
The cutouts segment the electrode current collector structure, allowing different sections to expand and contract independently during charging and discharging cycles. This reduces the cumulative stress on any single section, particularly at the vulnerable root of the tab portion, thereby preventing cracking while maintaining high volumetric energy density.
Solution Approach 2:
The cutouts are formed in advance in the root of the tab portion and its vicinity, creating stress relief zones before compression and cycling begin. These pre-formed openings act as cushioning elements that accommodate the expansion and contraction of the active material layer, preventing cracking before it can occur during normal battery operation.
Data Source
AI summary
A battery electrode which is one example of an embodiment is provided with a core and an active material layer disposed on the surface of the core. The core has a based part where the core surface is covered by the active material layer and a tab part projecting from the based part. Notches are formed on the core from the base of the tab part to the base part, or at positions where the base part adjoins the tab part. The edge of each notch is formed from a first curve comprising a first arc and either a second curve comprising a second arch having a smaller curvature than the first arc or a straight line. This allows a battery electrode to be provided such that the occurrence of cracks at the base of the tab part of the core and in the vicinity thereof can be sufficiently suppressed.