Patterned Calendered Electrode for Battery Ion Transport
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Solution Overview
Problem
Current methods for calendering electrodes in battery cells for vehicles result in reduced effectiveness due to lack of spatial variation in density and porosity, limiting the utilization of active materials.
Innovation Solution
A method involving a coated electrode with selective patterning and calendering to create regions of varying active material density and porosity, achieved through processes like subtractive patterning and controlled drying, enhances ion transport by creating spatial variations in the electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a thicker current collector or electrode is used to increase active material capacity, then the battery cell capacity increases, but the spatial variation in density and porosity decreases leading to reduced effectiveness of active materials
Solution Approach 1:
The electrode is designed with spatially varying density and porosity characteristics. Specifically, the electrode includes a first region with a first density and porosity, and a second region with a second density and porosity that differs from the first region. This local variation in properties allows different zones of the electrode to optimize for different functions, maintaining effectiveness even in thicker electrodes.
Solution Approach 2:
The electrode is segmented into multiple regions with distinct density and porosity characteristics. By dividing the electrode structure into zones with different properties (e.g., high porosity regions for ion transport, high density regions for active material loading), the overall electrode can achieve both high capacity and high effectiveness.
2Ease of manufacture
If uniform calendering is applied to the electrode, then manufacturing simplicity is maintained, but spatial variation in density and porosity is lost reducing active material utilization
Solution Approach 1:
The electrode structure is prepared in advance with specific density and porosity variations before final calendering. The slurry coating process is designed to create non-uniform active material distribution, and the drying process is controlled to establish the desired spatial variation. This preliminary structuring allows subsequent uniform calendering to produce the final varied density electrode without requiring complex variable pressure calendering equipment.
3Quantity of substance
If the electrode density is increased to improve energy density, then battery energy density improves, but ion transport capability decreases due to reduced porosity
Solution Approach 1:
Different regions of the electrode are assigned different density and porosity values optimized for their specific functions. Regions requiring high ion transport (such as near current collectors or in high current density areas) are designed with higher porosity, while regions prioritized for energy storage are designed with higher density. This local optimization allows the overall electrode to achieve high energy density while maintaining adequate ion transport capability where needed.
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 method improves the utilization of active materials by creating calendered electrodes with enhanced ion transport capabilities, optimizing the distribution of active materials for improved battery performance.
Implementation Method 1
drying the coated electrode at a temperature of between about 70 degrees Celsius (C) and about 150 C for between about 0 minutes and about 60 minutes
Implementation Method 2
compressing the patterned electrode by calendering the first surface to provide the first portion having a first density of active materials and the second portion having a second density of active materials
Data Source
AI summary
A method of making a calendered electrode for a battery cell comprises introducing a coated electrode having a first surface extending thereover. The coated electrode has a predetermined density of active materials for ion transport. The method further comprises selectively modifying the coated electrode by patterning the first surface to define a patterned electrode having a first portion and a second portion. After the step of selectively modifying, the method further comprises compressing the patterned electrode by calendering the first surface to provide the first portion having a first density of active materials and the second portion having a second density of active materials. The second density is greater than the first density to define the calendered electrode having a spatial variation of active material density.