Jelly-Roll Electrode Assembly Buffer Layer for Volume-Change Stability
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Solution Overview
Problem
Lithium batteries face challenges in achieving high capacity, reduced size, and improved structural stability due to volume changes in electrode assemblies, leading to potential structural integrity issues in compact designs.
Innovation Solution
Incorporating a buffer layer at the outermost region of the electrode assembly, which includes bent portions and an embossed structure, to absorb and mitigate volume changes during charging and discharging, thereby enhancing structural stability and preventing cracks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the battery size is reduced to achieve high loading capacity, then the energy density improves, but the structural stability deteriorates due to volume changes of electrode assemblies
Solution Approach 1:
The patent applies beforehand cushioning by introducing a buffer layer at the outermost region of the electrode assembly before volume changes occur. This buffer layer, with different physical properties than the electrode active material, is pre-positioned to absorb and mitigate stress from subsequent volume expansions and contractions during charging and discharging cycles, preventing structural degradation while maintaining compact battery design
2Stability of the object's composition
If the electrode assembly volume is increased to improve structural stability, then the structural integrity improves, but the battery size increases reducing loading capacity
Solution Approach 1:
The patent applies local quality by placing the buffer layer specifically at the outermost region of the electrode assembly where volume changes generate the most stress. This localized approach provides structural stability exactly where needed during charging/discharging cycles, rather than uniformly increasing the entire battery volume, thus maintaining high loading capacity while ensuring structural integrity at critical stress points
3Stability of the object's composition
If a buffer layer is added to absorb volume changes, then the structural stability improves, but the device complexity increases
Solution Approach 1:
The patent applies flexible shells and thin films by using a buffer layer in the form of a thin film structure at the outermost region of the electrode assembly. This thin film buffer layer provides the necessary stress absorption and structural stability while adding minimal complexity to the overall electrode assembly structure, avoiding the need for complex mechanical support 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 buffer layer effectively absorbs volume changes, reducing stress and preventing degradations, resulting in improved structural integrity and extended battery life, especially in compact designs.
Implementation Method 1
a first buffer portion on an outermost region of the electrode assembly and extendible along at least one of a winding direction of the electrode assembly and an opposite direction thereof
Data Source
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AI summary
An electrode assembly includes a first electrode, a second electrode, and a separator between the first electrode and the second electrode, the first electrode, the separator, and the second electrode being wound in a jelly-roll shape, and a first electrode tab, wherein the first electrode includes a first coated portion coated with a first electrode active material on a first substrate, and a first uncoated portion on the first substrate, on one side of the first coated portion, and free of the first electrode active material, wherein the first electrode tab is on the first uncoated portion of the first electrode, and wherein the first electrode further includes a first buffer portion on an outermost region of the electrode assembly and extendible along at least one of a winding direction of the electrode assembly and an opposite direction thereof.