Dry Electrode Film Gradient Porosity for Thick Lithium Batteries
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Solution Overview
Problem
Lithium batteries face challenges in achieving high energy density and miniaturization while minimizing solvent usage, as excess solvent is unavoidable in traditional electrode manufacturing methods, leading to increased internal resistance and decreased cycling performance.
Innovation Solution
A dry electrode film with increased porosity on both sides, featuring a gradient porosity structure, is used to enhance electrolyte immersion properties, reducing internal resistance and maintaining high energy density even with increased thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a dry electrode film with increased thickness is used to maintain high energy density, then energy density is improved, but internal resistance increases and cycling performance deteriorates
Solution Approach 1:
The electrode film employs a gradient porosity structure where the porosity varies through the thickness direction. Specifically, the porosity is higher in regions closer to the electrolyte contact surface and lower in the central region. This local variation in porosity allows electrolyte to efficiently penetrate and wet the electrode material throughout the thickness, ensuring good ionic conductivity and electrochemical performance even in thick electrodes, thereby maintaining cycling performance while achieving high energy density.
2Ease of manufacture
If traditional slurry method with excess solvent is used to manufacture electrodes, then manufacturing ease is improved, but solvent utilization efficiency deteriorates and internal resistance increases
Solution Approach 1:
The invention extracts and eliminates the solvent component from the traditional slurry electrode manufacturing process. Instead of using a wet slurry that requires drying and leaves residual solvent, the patent employs a dry pressing method where powder materials are directly compressed into the electrode film form. This extraction of solvent eliminates the associated losses, reduces internal resistance, and improves manufacturing efficiency without requiring complex drying or solvent recovery systems.
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 dry electrode film improves electrolyte penetration and cycling performance by reducing internal resistance and maintaining energy density, even with increased thickness, thus addressing the limitations of traditional lithium battery manufacturing.
Implementation Method 1
a dry electrode film which has improved electrolyte immersion properties by having increased porosity on at least one side
Data Source
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AI summary
A dry electrode film, and a dry electrode and a lithium battery, including the same, are provided, the dry electrode film including a first region having a first side surface provided at one end of a width direction perpendicular to a thickness direction of the dry electrode film and including a first dry electrode active material layer, a second region having a second side surface opposite to the first side surface and including a second dry electrode active material, and a third region provided between the first region and the second region and including a third dry electrode active material, wherein the third region has a third porosity less than a first porosity of the first region and a second porosity of the second region.