Non-Aqueous Battery Electrode Layout for Capacity Recovery
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Solution Overview
Problem
Lithium ion batteries for EVs experience significant capacity decrease during long-term storage, necessitating improvements in battery design to maintain capacity and enhance recovery rates.
Innovation Solution
The non-aqueous electrolyte secondary battery design includes specific dimensions for positive electrode active material application, such as a peripheral length of 0.28 m/Ah or less per unit battery capacity, and an area ratio of 85% to 95% for the facing region of the negative electrode active material, along with a high capacity per unit area of the positive electrode core, to minimize lithium ion dispersion in non-facing regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the positive electrode active material is applied to a larger peripheral length of the positive electrode core, then the battery capacity increases, but the capacity recovery rate after long-term storage decreases
Solution Approach 1:
The patent applies active material to specific regions of the electrode core with controlled peripheral length. By limiting the peripheral length to 0.28 m/Ah or less, the design creates a localized quality distribution where active material is strategically placed to balance capacity and storage stability, preventing excessive lithium ion dispersion in non-facing regions during storage.
Solution Approach 2:
The patent changes the geometric parameter of peripheral length per unit battery capacity to 0.28 m/Ah or less. This parameter optimization resolves the contradiction by establishing a quantitative relationship between electrode geometry and storage performance, enabling high capacity while maintaining 80% or more capacity recovery rate after 300 days of storage.
2Reliability
If the area ratio of the facing region of negative electrode active material is increased, then lithium ion dispersion in non-facing regions is reduced, but the battery capacity decreases
Solution Approach 1:
The patent optimizes the area ratio parameter of the facing region to fall within 85-95% of the entire negative electrode active material area. This parameter range achieves the optimal balance between reducing lithium ion dispersion (improving recovery rate) and maintaining sufficient battery capacity, resolving the technical contradiction between reliability and quantity of substance.
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 maintains an 80% capacity recovery rate after 300 days of storage, meeting the performance requirements for EV batteries and improving energy density.
Implementation Method 1
a positive electrode plate including a positive electrode core and a positive electrode active material applied to at least one surface of the positive electrode core, and a negative electrode plate including a negative electrode core and a negative electrode active material applied to the negative electrode core
Implementation Method 2
the positive electrode plate and the negative electrode plate are stacked with a separator interposed therebetween
Data Source
AI summary
A non-aqueous electrolyte secondary battery includes an electrode body including a positive electrode plate and a negative electrode plate, a rectangular exterior body having an opening and accommodating the electrode body, a sealing plate sealing the opening, and an electrode terminal provided to the sealing plate. The positive electrode plate includes a positive electrode core and a positive electrode active material applied to both surfaces of the positive electrode core. The peripheral length of a positive electrode core portion to which the positive electrode active material is applied is 0.28 m/Ah or less per unit battery capacity.