Secondary Battery Electrolyte Composition for Low-Temperature Cycling
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Solution Overview
Problem
Secondary batteries experience a significant drop in charge and discharge performance at low temperatures and increased swelling with cycle life, affecting their cycle performance and service life.
Innovation Solution
The use of an electrolyte with a specific mass ratio of cyclic carbonate to chain carbonate, where dimethyl carbonate constitutes between 9 wt% and 50 wt% of the chain carbonate, and a carboxylic acid ester content less than 5 wt%, optimizes both low-temperature power and cycle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the electrolyte uses conventional composition ratios, then the battery structure is simple, but the low-temperature power and cycle performance deteriorate
Solution Approach 1:
The patent applies parameter changes by precisely controlling the mass ratio of cyclic carbonate to chain carbonate (25:75 to 32:68) and the mass percentage of dimethyl carbonate in chain carbonate (9 wt% to 50 wt%). This specific parameter optimization resolves the contradiction by achieving excellent cycle performance through controlled composition ratios rather than simple or arbitrary formulations.
Solution Approach 2:
The patent uses composite materials by combining cyclic carbonate and chain carbonate in specific proportions to create an optimized electrolyte formulation. This composite approach allows the electrolyte to simultaneously achieve good cycle performance and low-temperature power characteristics that neither component could provide alone in conventional ratios.
2Reliability
If the content of carboxylic acid ester is not strictly controlled, then the electrolyte formulation is simple, but the cycle performance is seriously affected
Solution Approach 1:
The patent applies parameter changes by setting a specific upper limit for carboxylic acid ester content (less than 5 wt%) in the electrolyte. This parameter control resolves the contradiction by ensuring cycle performance through controlled purity standards, making the manufacturing process require precise but straightforward compositional control.
3Adaptability or versatility
If the battery operates at low temperature, then the operating range is extended, but the charge and discharge performance drops sharply
Solution Approach 1:
The patent applies parameter changes by optimizing the electrolyte composition with specific ratios of cyclic carbonate to chain carbonate (25:75 to 32:68) and controlling dimethyl carbonate content (9 wt% to 50 wt%). This composition optimization resolves the contradiction by maintaining good low-temperature power characteristics while extending the operational temperature range of the battery.
4Duration of action of moving object
If the battery undergoes charge and discharge cycles, then the energy storage function is fulfilled, but the swelling increases affecting service life
Solution Approach 1:
The patent uses composite materials by combining cyclic carbonate and chain carbonate in optimized proportions (mass ratio 25:75 to 32:68) with controlled dimethyl carbonate content (9 wt% to 50 wt%). This composite electrolyte formulation resolves the contradiction by reducing battery swelling during cycling, thereby extending service life and cycle durability.
Data Source
AI summary
The present application provides a secondary battery, an electrolyte, and an apparatus including the secondary battery. The secondary battery of the present application includes an electrolyte, characterized in that the electrolyte includes an organic solvent, and the organic solvent includes a cyclic carbonate and a chain carbonate; the mass ratio of the cyclic carbonate and the chain carbonate is from 25:75 to 32:68; the chain carbonate includes dimethyl carbonate; the mass percentage of the dimethyl carbonate in the chain carbonate is greater than or equal to 9 wt % and less than 50 wt %; wherein based on the total mass of the organic solvent, the mass percentage of a carboxylic acid ester is less than 5 wt %. The secondary battery of the present application can simultaneously obtain excellent low-temperature power, long service life and cycle performance.