Lithium Battery Electrode Assembly for Current Density Balance
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Solution Overview
Problem
The imbalance of current density between the tab and non-tab areas in lithium secondary battery electrodes leads to degradation and reduced capacity, necessitating a solution to enhance battery performance.
Innovation Solution
The electrode assembly design includes regions with varying current densities and hole area ratios, specifically higher in high current density areas, to balance lithium ion concentration and movement, thereby reducing degradation and increasing capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a tab is provided on one end portion of the electrode to enable current collection, then the electrode can be connected to the external circuit, but an imbalance of current density occurs between the tab area and non-tab area
Solution Approach 1:
The patent applies local quality by providing different hole area ratios in different regions of the electrode. Specifically, a first hole area ratio is provided in the tab area and a second hole area ratio is provided in the non-tab area, with the second ratio being greater than the first. This creates spatially varying properties that compensate for the current density imbalance caused by the tab structure, allowing each region to have optimized characteristics for its specific function.
2Reliability
If the hole area ratio is increased in high current density regions, then current density balance is improved, but the electrode structure becomes more complex
Solution Approach 1:
The patent segments the electrode into distinct regions based on current density characteristics. The electrode is divided into a tab area and a non-tab area, with each region assigned a specific hole area ratio appropriate for its current density level. This segmentation allows the complex requirement of current density balance to be addressed through region-specific simplifications rather than uniform complex design throughout.
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 improves battery capacity by 5-10% and reduces degradation rates, enhancing safety and lifetime by minimizing inactive lithium and uniform current distribution.
Implementation Method 1
A lithium secondary battery is a battery including a positive electrode and a negative electrode, each containing an active material capable of intercalation and deintercalation of lithium ions
Implementation Method 2
balance lithium ion concentration and movement
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
Disclosed herein are an electrode assembly for a lithium secondary battery and a lithium secondary battery including the same. The electrode assembly includes a negative electrode including a negative electrode current collector having one end portion on which a negative electrode tab is formed and a negative electrode active material layer positioned on at least one surface of the negative electrode current collector, and a positive electrode including a positive electrode current collector having one end portion on which a positive electrode tab is formed and a positive electrode active material layer positioned on at least one surface of the positive electrode current collector, wherein, in each of the negative electrode and the positive electrode, a region with a high current density and a region with a low current density are present when a voltage is applied to the electrode assembly, and a hole area ratio in the region with a high current density is greater than that in the region with a low current density.