Non-aqueous Electrolyte Secondary Cell Cycle Characteristics
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Solution Overview
Problem
Existing non-aqueous electrolyte secondary cells do not consistently exhibit excellent cycle characteristics over a wide temperature range from low to high temperatures.
Innovation Solution
A non-aqueous electrolyte secondary cell configuration with a positive electrode of lithium transition metal composite oxide, a negative electrode of carbon material, and a non-aqueous electrolyte solution, where the mass of the electrolyte solution per cell capacity is between 10.0 to 12.0 g/Ah and the volume of the electrolyte solution per void volume in the outer body is between 70 to 85%, ensuring sufficient electrolyte supply during charge and discharge cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrolyte amount is increased to improve cycle characteristics, then capacity retention improves, but energy density decreases
Solution Approach 1:
The patent applies parameter changes by precisely controlling the electrolyte amount within the range of 0.0056 to 0.0064 cc/mAh and the void volume ratio within 65% to 75%. This optimization balances the electrolyte quantity to maintain excellent cycle characteristics while preventing excessive electrolyte that would reduce energy density. The specific parameter ranges achieve the dual goal of improving reliability and maintaining energy efficiency.
2Reliability
If the electrolyte amount is increased to improve capacity retention at low temperature, then cycle performance improves, but cell volume increases
Solution Approach 1:
The patent optimizes the electrolyte amount parameter within the specific range of 0.0056 to 0.0064 cc/mAh and controls the void volume ratio between 65% to 75%. This precise parameter control ensures sufficient electrolyte for low-temperature capacity retention while minimizing the cell volume increase that would result from excessive electrolyte addition.
3Use of energy by moving object
If the electrolyte amount is optimized for high capacity, then energy density improves, but cycle life deteriorates
Solution Approach 1:
The patent identifies and applies optimal parameter ranges: electrolyte amount of 0.0056 to 0.0064 cc/mAh and void volume ratio of 65% to 75%. These parameter changes resolve the contradiction by finding the precise electrolyte quantity that maintains high energy density while ensuring sufficient electrolyte for long cycle life, particularly at low temperatures where electrolyte deficiency causes capacity degradation.
Data Source
AI summary
The non-aqueous electrolyte secondary cell comprises a positive electrode having a positive electrode active material composed of a lithium transition metal composite oxide, a negative electrode having a negative electrode active material composed of carbon material, a non-aqueous electrolyte solution, and an outer body in which the positive electrode, the negative electrode and the non-aqueous electrolyte solution are housed; the mass of the non-aqueous electrolyte solution per cell capacity of the non-aqueous electrolyte secondary cell is 10.0 to 12.0 g/Ah; and the volume of the non-aqueous electrolyte solution per void volume in the outer body is 70 to 85%.