Grooved Lithium-Ion Cathode Layer for Large-Area Low-Resistance Electrodes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Increasing the capacity of lithium-ion rechargeable batteries by enlarging the area of the electrode active material layers leads to undesirable increases in electrical resistance, which is particularly problematic for applications requiring a thin and flat battery design, such as those used in vehicles.
Innovation Solution
The electrode design includes a cathode active material layer with a large area and strategically formed grooves to limit the maximum distance between groove edges, maintaining a high aspect ratio and reducing the overall electrical resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the area of the electrode active material layer is increased to increase battery capacity, then the battery capacity increases, but the electrical resistance increases
Solution Approach 1:
The electrode active material layer is divided into multiple segments by forming grooves that extend from one surface to the opposite surface. These grooves partition the large-area electrode into smaller sections, reducing the maximum distance electrons must travel through the active material and thereby limiting the increase in electrical resistance while maintaining the overall large area for high capacity
2Quantity of substance
If the area of the electrode active material layer is increased to increase battery capacity, then the battery capacity increases, but the height of the battery increases
Solution Approach 1:
Instead of increasing battery capacity by stacking more cells vertically (increasing height), the invention expands the electrode area in the planar dimension (length and width). The grooves are formed extending through the thickness of the electrode, allowing the electrode to maintain a thin profile while achieving large effective area through horizontal expansion rather than vertical stacking
3Quantity of substance
If the area of the electrode active material layer is increased to increase battery capacity, then the battery capacity increases, but the electrical resistance increases undesirably
Solution Approach 1:
The grooves segment the electrode active material layer into multiple regions, creating shorter current paths within each segment. This segmentation reduces the maximum distance charge carriers must travel, thereby limiting the increase in electrical resistance that would otherwise occur with large-area electrodes
Solution Approach 2:
The grooves are strategically positioned to create regions of different characteristics within the electrode. By controlling the spacing and dimensions of the grooves, the electrode structure is optimized to maintain low electrical resistance locally within each segment while achieving high overall capacity through the cumulative effect of multiple segments
Data Source
AI summary
An electrode includes a current collector and a cathode active material layer formed on a surface of the current collector. The area of the cathode active material layer is greater than or equal to 1 m2. The cathode active material layer includes a main surface located on a side opposite to a surface facing the current collector, and a groove that opens in the main surface. In plan view of the main surface, a maximum distance, which is the maximum value of a specific distance, is less than or equal to 60 mm. A part of the main surface in which the groove is not provided is referred to as an island. The specific distance is the shorter one of the distance between an arbitrary point in the island and an outer peripheral edge of the cathode active material layer, and the distance between the arbitrary point and the groove.