Electrolyte Composition for High-Voltage Battery Expansion Control
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Solution Overview
Problem
High-voltage electrochemical devices face challenges with cathode material stability, non-aqueous electrolyte decomposition, and increased battery capacity attenuation due to floating-charge performance issues.
Innovation Solution
An electrolyte composition including a fluorinated cyclic carbonate, a multi-nitrile compound with an ether bond, and a cyclic carbonate with a carbon-carbon double bond, where the weight percentage of the fluorinated cyclic carbonate is greater than that of the multi-nitrile compound, effectively controlling battery expansion and enhancing cycle, storage, and floating-charge performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high-voltage cathode material is used to increase energy density, then energy density is improved, but cathode material stability deteriorates and electrolyte decomposition increases
Solution Approach 1:
The patent introduces a specific electrolyte additive (containing fluorinated cyclic carbonate, multi-nitrile compound with ether bond, and cyclic carbonate with carbon-carbon double bond) as an intermediary substance between the high-voltage cathode material and the non-aqueous electrolyte. This additive forms a protective interface layer that mediates the interaction, preventing direct harmful reactions while enabling high-voltage operation.
Solution Approach 2:
The patent modifies the chemical composition parameters of the electrolyte system by incorporating specific compounds with defined weight percentages (fluorinated cyclic carbonate: 0.1-10%, multi-nitrile compound: 0.1-5%, cyclic carbonate with double bond: 0.1-5%). These parameter changes transform the electrolyte's properties to enable stable operation at high voltages.
2Ease of operation
If floating charge is applied to maintain full charge state, then battery readiness is improved, but thickness expansion and capacity attenuation increase
Solution Approach 1:
The patent applies preliminary action by having the electrolyte additive form a protective film on the cathode surface before floating charge occurs. This pre-formed protective layer prevents subsequent degradation reactions that would normally occur during prolonged floating charge, thereby maintaining both readiness and reliability.
3Ease of manufacture
If conventional electrolyte composition is used, then manufacturing simplicity is maintained, but high-temperature storage performance deteriorates
Solution Approach 1:
The patent creates a composite electrolyte system by combining multiple components (fluorinated cyclic carbonate, multi-nitrile compound with ether bond, cyclic carbonate with carbon-carbon double bond, and standard electrolyte solvents) in specific proportions. This composite approach enhances high-temperature storage performance while maintaining manufacturing feasibility through straightforward mixing processes.
Data Source
Figure 1~3
AI summary
An electrolyte includes a fluorinated cyclic carbonate, a multi-nitrile compound having an ether bond and a cyclic carbonate having a carbon-carbon double bond. Based on a total weight of the electrolyte, a weight percentage (Cf) of the fluorinated cyclic carbonate is greater than a weight percentage (Cn) of the multi-nitrile compound having an ether bond. The electrolyte of the present application can control the expansion of the electrochemical device, so that the electrochemical device has excellent cycle, storage and/or floating-charge performance.