Lithium Secondary Battery Materials With 500 ppm Sodium Limit
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Solution Overview
Problem
The performance and lifetime characteristics of lithium secondary batteries are adversely affected by high sodium content, leading to reduced capacity and Coulomb efficiency due to sodium's presence in the positive electrode, negative electrode, and electrolyte solution, which causes side reactions and electrolyte consumption.
Innovation Solution
Minimizing the sodium content in lithium secondary batteries to no more than 500 ppm, specifically in the positive electrode binder, negative electrode, and electrolyte solution, to prevent capacity and efficiency degradation over charging/discharging cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sodium content is reduced to no more than 500 ppm, then battery performance and lifetime are improved, but manufacturing complexity increases due to stricter material purity requirements
Solution Approach 1:
The patent applies parameter changes by establishing specific quantitative limits for sodium content (no more than 500 ppm) in battery components. This transforms the qualitative goal of 'reducing impurities' into a measurable and controllable parameter, enabling systematic quality management while achieving improved battery performance and lifetime through minimized sodium content in the positive electrode, negative electrode, and electrolyte solution
2Reliability
If sodium content is minimized to prevent side reactions, then Coulomb efficiency is maintained, but material selection and processing become more difficult
Solution Approach 1:
The patent establishes a specific parameter threshold (sodium content ≤ 500 ppm) that balances the need to prevent side reactions and maintain Coulomb efficiency with the practical constraints of material availability and processing capabilities. This quantitative specification enables manufacturers to select appropriate materials and processes while ensuring the desired electrochemical performance
3Reliability
If stricter control of sodium content is implemented, then capacity reduction is prevented, but production cost increases
Solution Approach 1:
The patent defines a specific sodium content threshold (no more than 500 ppm) that is sufficient to prevent capacity reduction and maintain battery performance without imposing excessively stringent requirements that would dramatically increase production costs. This balanced parameter specification achieves reliable capacity retention while considering economic feasibility
Data Source
AI summary
A lithium secondary battery, and more particularly, to a lithium secondary battery having improved performance by minimizing the content of impurities such as sodium in the battery.