Lithium-Ion Battery Electrolyte Composition for Low-Electrolyte Cells
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Solution Overview
Problem
The insufficient electrolyte solution in lithium-ion batteries due to increased battery cell width and minimized redundant separator width affects battery performance, leading to potential micro-short circuits and reduced cycling performance.
Innovation Solution
Adjusting the content of fluoroethylene carbonate in the electrolyte solution based on the distance between the separator edges and the electrode plates, ensuring the relationship C≥B/20A+1, where C is the fluoroethylene carbonate content, A is the distance between separator edges, and B is the cavity height, to maintain optimal electrolyte levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the battery cell width is increased to improve energy, then the energy of the battery is improved, but the electrolyte solution becomes insufficient
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte solution by introducing fluoroethylene carbonate (FEC) with specific content ranges (2.25%-20%). This parameter change allows the electrolyte to provide sufficient functional components even when the total volume is reduced due to increased battery cell width, thereby resolving the contradiction between energy improvement and electrolyte insufficiency.
2Reliability
If the separator width is increased to prevent short circuit, then the reliability is improved, but the energy density deteriorates
Solution Approach 1:
The patent introduces fluoroethylene carbonate with specific content ranges (2.25%-20%) into the electrolyte solution. This chemical parameter change allows the battery to maintain higher energy density while the separator maintains its protective function, as the enhanced electrolyte composition compensates for the space occupied by the wider separator.
Data Source
AI summary
A battery includes: a housing having a cavity; a battery cell arranged in the cavity, the battery cell including a positive electrode plate, a negative electrode plate, and a separator; and an electrolyte solution filled in the battery cell including fluoroethylene carbonate. A width of the separator is greater than that of the positive and the negative electrode plate. The battery satisfies following relationship: C≥B/20A+1, where a content of fluoroethylene carbonate in the electrolyte solution is C %, A represents a distance between an edge of the separator and that of an electrode plate on the same side, and B represents a height of the cavity. When the foregoing relationship is satisfied, deterioration of performance of the battery cell caused by insufficient electrolyte solution may be alleviated, thereby improving a value of a self-discharge coefficient k and cycling performance of the battery.