Grooved Lithium Battery Electrode Plate Design for Impregnation
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Solution Overview
Problem
In lithium secondary batteries, the increased filling density of active materials in electrode plates makes it difficult to impregnate a nonaqueous electrolyte, leading to nonuniform distribution and reduced capacity, and the formation of grooves to aid impregnation can cause deformation and fractures during winding, affecting productivity and reliability.
Innovation Solution
The electrode plate design features grooves only on both-surface coated parts, not on one-surface coated parts, to reduce tensile stress and prevent deformation, ensuring better impregnation and stability during winding and stacking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If grooves are formed in surfaces of electrode plates to improve electrolyte impregnation, then electrolyte distribution is improved, but tensile stress concentrates at groove roots causing fractures during winding
Solution Approach 1:
The groove depth is made non-uniform across the electrode plate surface, with shallower grooves in regions prone to high tensile stress during winding and deeper grooves in regions with lower stress. This local variation in groove depth optimizes electrolyte impregnation while preventing stress concentration-induced fractures at groove roots.
Solution Approach 2:
The groove depth parameter is varied continuously or discontinuously across different regions of the electrode plate. By changing the depth parameter spatially, the design achieves optimal balance between electrolyte access (requiring deeper grooves) and mechanical strength (requiring shallower grooves to avoid stress concentration).
2Quantity of substance
If filling density of active material is increased to enhance capacity, then battery capacity increases, but porosity is reduced making electrolyte impregnation difficult
Solution Approach 1:
Grooves are formed in the active material layer surface to create controlled porous pathways that facilitate electrolyte penetration. These grooves provide direct channels for electrolyte to reach deeper regions of the high-density active material, overcoming the reduced porosity caused by increased filling density.
Solution Approach 2:
The continuous active material layer is effectively segmented by the grooves into multiple regions, creating a hierarchical structure where the grooves serve as electrolyte channels and the segmented active material regions maintain high filling density. This segmentation allows electrolyte access without sacrificing overall capacity.
3Loss of time
If width and depth of grooves are increased to reduce impregnation time, then electrolyte distribution improves, but amount of active material is reduced causing capacity loss
Solution Approach 1:
Groove dimensions are optimized locally rather than uniformly across the entire electrode plate. Regions with poorer electrolyte access receive deeper or wider grooves to reduce impregnation time, while regions with good access maintain shallower grooves to preserve active material content and capacity.
Solution Approach 2:
Instead of forming grooves uniformly across the entire electrode surface, grooves are strategically placed only in regions where they are most needed for electrolyte distribution. This partial action approach reduces the total active material removed while still achieving effective impregnation in critical areas.
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
This design enhances electrolyte impregnation, prevents deformation and fractures, and improves the productivity and reliability of lithium secondary batteries by maintaining even electrolyte distribution and reducing winding issues.
Implementation Method 1
it becomes difficult to impregnate a nonaqueous electrolyte with a relatively high viscosity, which has been injected into a battery case, into small gaps in an electrode group
Data Source
AI summary
An electrode plate includes a both-surface coated part 14 in which an electrode active material layer 13 is provided on both surfaces of a current collector core material 12, a core material exposed part 18 in which the negative electrode active material layer 13 is not provided, and a one-surface coated part 17 in which the negative electrode active material layer 13 is provided on only one surface of the current collector core material 12. A plurality of grooves 10 are formed in both surfaces of the both-surface coated part 14 and the grooves 10 are not formed in the one-surface coated part 17.