Electrolyte Kinetic Factor Tuning for Lithium-Ion Rate Stability
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Solution Overview
Problem
Lithium ion batteries face challenges in achieving higher energy density, charging/discharging efficiency, and cycling stability due to the high cost of unconventional additives used to modify the interface layer, which affects conductivity and impedance.
Innovation Solution
An energy storage apparatus with an electrolytic solution having a kinetic factor α in the range of −10≤α≤30, controlled by viscosity and conductivity correction coefficients, is used to optimize the migration of electrolyte cations, ensuring efficient intercalation and deintercalation, thereby improving rate and cycling performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If unconventional additives are added into the electrolytic solution to modify the interface layer, then the impedance is reduced and conductivity is improved, but the production cost of the battery increases
Solution Approach 1:
The patent applies parameter changes by introducing a kinetic factor α that combines multiple electrolyte properties (viscosity, diffusion coefficient, conductivity, temperature, and concentration) into a single optimized parameter. By controlling the kinetic factor within a specific range, the patent achieves improved conductivity and interface layer modification without requiring expensive unconventional additives, thus resolving the contradiction between reliability improvement and manufacturing cost increase
Solution Approach 2:
The patent employs composite materials by formulating an electrolytic solution that combines conventional additives with specific solvents and electrolyte salts in optimized proportions. The electrolytic solution contains cyclic carbonates (EC, PC), chain carbonates (DMC, DEC, EMC), and conventional additives (VC, FEC, GBL) in a composite formulation that achieves the desired kinetic factor range, providing both cost-effectiveness and performance improvement
2Productivity
If the kinetic factor of the electrolytic solution is optimized to improve dynamic performance, then rate performance and cycling stability are enhanced, but the formulation complexity increases
Solution Approach 1:
The patent merges multiple electrolyte properties (viscosity, diffusion coefficient, conductivity, temperature, and concentration) into a single kinetic factor α that can be controlled within a specific range. This consolidation simplifies the optimization process by providing a unified parameter that encompasses all these properties, allowing for improved rate performance and cycling stability without proportionally increasing formulation complexity
Solution Approach 2:
The kinetic factor α serves as a universal parameter that simultaneously optimizes multiple aspects of battery performance including rate performance, cycling stability, and interface layer formation. By controlling this single parameter, the patent achieves multi-functional optimization of the electrolytic solution, reducing the need for separate adjustments of individual properties
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
The solution enhances the energy storage apparatus' dynamic performance, maintaining stable operation and preventing lithium precipitation, thus achieving better capacity retention and low-temperature performance.
Implementation Method 1
the electrolytic solution has a kinetic factor α satisfying the following formula: α=k1×ε×lnD+k2×σ×T/100C; the kinetic factor α of the electrolytic solution is in the range of −10≤α≤30, ε is viscosity of the electrolytic solution, D is diffusion coefficient of electrolyte cations in the electrolytic solution, σ is conductivity of the electrolytic solution
Implementation Method 2
D is diffusion coefficient of electrolyte cations in the electrolytic solution
Data Source
AI summary
An energy storage apparatus, an energy storage system, and an electric device. The energy storage apparatus includes an electrolytic solution, a positive electrode sheet, a separator, and a negative electrode sheet. The kinetic factor α of the electrolytic solution satisfies the formula: α=k1×ε×lnD+k2×σ×T/100C and the kinetic factor α of the electrolytic solution satisfies: −10≤α≤30, wherein ε is the viscosity of the electrolytic solution, D is the diffusion coefficient of electrolyte cations in the electrolytic solution, σ is the electrical conductivity of the electrolytic solution, T is the thermodynamic temperature of the electrolytic solution, C is the molar concentration of an electrolyte, k1 is the viscosity correction coefficient of the electrolytic solution, and k2 is the electrical conductivity correction coefficient of the electrolytic solution.