Secondary Battery Electrode Electrolytes for SEI and CEI Formation
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Solution Overview
Problem
Existing secondary batteries using a single electrolytic solution on both the negative and positive electrodes result in suboptimal formation of Solid Electrolyte Interface (SEI) and Cathode Electrolyte Interface (CEI) films, leading to deteriorated performance.
Innovation Solution
A manufacturing method where the composition ratios of the electrolytic solutions on the negative and positive electrodes are intentionally made different to facilitate the formation of better SEI and CEI films, using specific solvents and additives tailored for each electrode.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single electrolytic solution is used on both negative and positive electrodes, then the manufacturing process is simple, but the SEI and CEI films are suboptimally formed leading to deteriorated battery performance
Solution Approach 1:
The electrolytic solution is segmented into two distinct compositions: a first electrolytic solution for the negative electrode and a second electrolytic solution for the positive electrode. This segmentation allows each electrode to receive an electrolytic solution optimized for its specific requirements, enabling optimal SEI and CEI film formation while maintaining a relatively simple manufacturing process through separate application steps.
Solution Approach 2:
Different electrolytic solutions with tailored compositions are applied to different locations (electrodes) within the battery system. The first electrolytic solution contains specific solvents and additives optimized for negative electrode SEI formation, while the second electrolytic solution contains different solvents and additives optimized for positive electrode CEI formation, achieving local optimization of film quality.
2Reliability
If different composition ratios of electrolytic solutions are used on negative and positive electrodes, then better SEI and CEI films are formed, but the manufacturing process becomes more complex
Solution Approach 1:
The electrolytic solution system is segmented into two independently formulated solutions with different composition ratios. The first electrolytic solution contains solvents and additives in ratios optimized for negative electrode SEI formation, while the second electrolytic solution contains different solvents and additives in ratios optimized for positive electrode CEI formation, allowing each electrode to achieve optimal film quality.
Solution Approach 2:
The composition parameters of the electrolytic solutions are changed and optimized for each electrode type. By adjusting solvent types, solvent ratios, and additive concentrations in the first electrolytic solution for the negative electrode and differently adjusting these parameters in the second electrolytic solution for the positive electrode, optimal SEI and CEI films are formed.
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
Improves the performance of secondary batteries by enhancing the quality of SEI and CEI films, resulting in higher capacity retention and reduced impedance, thus extending the battery's lifespan and efficiency.
Implementation Method 1
a separator permeable to the first electrolytic solution and the second electrolytic solution
Data Source
Figure 1~2
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AI summary
A manufacturing method for improving the performance of a secondary battery is realized. The manufacturing method includes: forming a negative electrode containing a negative electrode active material and a first electrolytic solution; forming a positive electrode containing a positive electrode active material and a second electrolytic solution; forming a cell in which a separator is located between the negative electrode and the positive electrode; and performing preliminary charging on the cell. A composition ratio of components contained in the first electrolytic solution and a composition ratio of components contained in the second electrolytic solution are different from each other.