Secondary Battery Swelling Control via Electrolyte and Electrode Ratios
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Solution Overview
Problem
Secondary batteries face challenges in achieving superior swelling characteristics and charge characteristics while maintaining sufficient energy density, with existing configurations not fully optimizing the performance of their components.
Innovation Solution
A secondary battery design incorporating a lithium-nickel composite oxide positive electrode, a lithium-titanium composite oxide negative electrode, and an electrolytic solution containing a dinitrile compound and a carboxylic acid ester, with specific capacity and mole ratios to enhance swelling and charge performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a secondary battery uses conventional electrode and electrolyte configurations, then manufacturing and operation are simpler, but swelling characteristic and charge characteristic are insufficient
Solution Approach 1:
The patent applies parameter changes by optimizing the molar ratio of dinitrile compound to carboxylic acid ester in the electrolyte (set to 1%≤ ratio ≤4%), and optimizing the capacity ratio of positive to negative electrode (set to 100%≤ ratio ≤120%). These specific parameter ranges resolve the contradiction by achieving superior swelling and charge characteristics while maintaining reasonable device complexity.
Solution Approach 2:
The patent uses composite materials by combining dinitrile compound and carboxylic acid ester in the electrolyte, and using lithium-nickel composite oxide and lithium-titanium composite oxide in the electrodes. This composite approach enables the battery to achieve both low-temperature output characteristics and reduced gas generation, resolving the swelling and charge characteristic issues.
2Reliability
If the battery prioritizes swelling and charge characteristics through specific material ratios, then performance improves, but energy density may be compromised
Solution Approach 1:
The patent resolves this contradiction by optimizing the capacity ratio parameter between positive and negative electrodes (100%≤ ratio ≤120%). This parameter optimization ensures that the battery achieves superior charge characteristics while maintaining high energy density, as the balanced capacity ratio allows efficient utilization of both electrodes without excessive material usage.
Solution Approach 2:
The patent applies local quality by using different composite oxide materials in specific electrode locations - lithium-nickel composite oxide in the positive electrode and lithium-titanium composite oxide in the negative electrode. Each material is selected for its specific local function: the nickel composite provides high capacity while the titanium composite suppresses gas generation, achieving both performance and energy density goals.
3Reliability
If the electrolyte uses dinitrile compound and carboxylic acid ester in specific ratios, then oxidation resistance improves, but manufacturing precision requirements increase
Solution Approach 1:
The patent resolves this contradiction by setting a relatively wide acceptable range for the molar ratio parameter (1%≤ ratio ≤4%), which provides manufacturing flexibility while still achieving the desired oxidation resistance. This parameter range is wide enough to accommodate normal manufacturing variations but narrow enough to ensure performance, thus resolving the contradiction between reliability and manufacturing precision.
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 configuration achieves superior swelling and charge characteristics while securing energy density, with the dinitrile compound improving oxidation resistance and the lithium-titanium composite oxide suppressing gas generation, leading to improved lithium-ion entry performance and reduced battery swelling.
Implementation Method 1
the dinitrile compound improving oxidation resistance
Implementation Method 2
the lithium-titanium composite oxide suppressing gas generation
Implementation Method 3
improved lithium-ion entry performance
Data Source
AI summary
A secondary battery includes a positive electrode, a negative electrode, and an electrolytic solution. The positive electrode includes a lithium-nickel composite oxide. The negative electrode includes a lithium-titanium composite oxide. The electrolytic solution includes a dinitrile compound and a carboxylic acid ester. A ratio of a capacity per unit area of the positive electrode to a capacity per unit area of the negative electrode is greater than or equal to 100% and less than or equal to 120%. A ratio of a number of moles of the dinitrile compound to a number of moles of the carboxylic acid ester is greater than or equal to 1% and less than or equal to 4%.