Lithium Secondary Battery Electrolyte Reinjection Before Capacity Fade
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Solution Overview
Problem
The commercialization of lithium-sulfur batteries is hindered by capacity and lifetime degradation due to polysulfide elution and electrolyte depletion during charge and discharge cycles, which is exacerbated by improper electrolyte injection and volume expansion of the negative electrode.
Innovation Solution
A method is introduced to enhance lithium secondary battery lifetime by injecting a specific amount of electrolyte liquid before a certain point in the charge and discharge cycle, specifically earlier than half the cycle at which discharge capacity reaches 80% of initial capacity, to maintain optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrolyte liquid is injected in excess to ensure sufficient impregnation, then electrochemical performance is improved, but lithium polysulfide elution increases accelerating lifetime degradation
Solution Approach 1:
The invention changes the parameter of electrolyte injection timing from a static initial injection to a dynamic multi-stage injection process. Additional electrolyte is injected at specific cycle points (e.g., when discharge capacity reaches 80% of initial capacity), adapting the electrolyte amount to the battery's changing needs during operation and thereby extending lifetime while maintaining performance
2Duration of action of stationary object
If electrolyte liquid is injected in small amount to reduce polysulfide elution, then battery lifetime is extended, but performance is not properly obtained due to overvoltage
Solution Approach 1:
The invention implements periodic additional injection of electrolyte liquid at specific charge-discharge cycle intervals. This periodic supplementation ensures that electrolyte volume is maintained at optimal levels throughout the battery's operation, preventing both overvoltage conditions and excessive polysulfide elution, thus balancing performance and lifetime
3Reliability
If proper amount of electrolyte liquid is injected initially, then electrochemical performance is optimized, but electrolyte liquid is depleted by volume expansion of negative electrode during charge and discharge cycles causing overvoltage
Solution Approach 1:
The invention performs preliminary additional injection of electrolyte liquid at predetermined cycle points before complete depletion occurs. By proactively supplementing electrolyte volume in advance (e.g., when discharge capacity reaches 80% of initial capacity), the system prevents overvoltage conditions and maintains optimal electrochemical performance throughout extended operation
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 approach effectively extends the cycle life of lithium secondary batteries by stabilizing capacity and reducing degradation, demonstrating a 50% increase in cycle lifetime compared to conventional methods.
Implementation Method 1
a non-aqueous electrolyte including a lithium salt is impregnated into an electrode assembly including a positive electrode and a negative electrode
Implementation Method 2
a carbon-based material having intercalation and deintercalation of metal ions such as lithium ions
Implementation Method 3
silicon or tin forming an alloy with lithium as a negative electrode active material
Implementation Method 4
the electrolyte liquid is depleted by a volume expansion of a negative electrode as a charge and discharge cycle progresses
Data Source
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AI summary
The present invention relates to a method for enhancing a lifetime of a lithium secondary battery including manufacturing a battery by injecting an electrolyte liquid to an electrode assembly-embedded battery; and charging and discharging the manufactured battery, and additionally injecting an electrolyte liquid earlier than half a cycle point with respect to the number of charge and discharge cycles reaching discharge capacity of 80% compared to initial capacity.