Lithium Ion Capacitor Pre-doping via Compression and Fast Conditioning
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Solution Overview
Problem
Conventional methods for pre-doping lithium ion capacitors are time-consuming and costly, requiring slow charge-discharge rates and the use of lithium metal electrodes, which pose safety issues and complexity.
Innovation Solution
A rapid pre-doping method involving compressing a lithium ion capacitor to insert lithium ions into the anode carbon structure, followed by conditioning through fast charging and discharging, which significantly reduces the pre-doping time from hours to minutes and eliminates the need for lithium metal electrodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If conventional pre-doping methods are used, then lithium ions are inserted into the anode carbon structure, but the process is time-consuming and costly
Solution Approach 1:
The patent applies parameter changes by modifying the charge-discharge rates during pre-doping. Instead of using slow conventional rates, the method employs accelerated rates (e.g., 1C, 3C, or 5C rates) to significantly reduce pre-doping time from hours to minutes, thereby improving manufacturing efficiency while maintaining effective lithium ion insertion
Solution Approach 2:
The patent implements preliminary action by performing pre-doping as an integrated step during the initial cell formation process rather than as a separate, time-consuming preparatory step. This approach combines multiple functions (formation and pre-doping) into one operation, reducing total process time and cost
2Ease of manufacture
If lithium metal electrodes are used for pre-doping, then lithium ions are supplied to the anode, but safety issues and complexity arise
Solution Approach 1:
The patent applies the extraction principle by removing lithium metal electrodes from the pre-doping process entirely. Instead, lithium ions are supplied through the electrolyte during normal charge-discharge cycles, eliminating the safety hazards and manufacturing complexity associated with handling and assembling lithium metal components
Solution Approach 2:
The system performs self-service by using the capacitor's own electrolyte and electrochemical reactions to supply lithium ions during pre-doping. The electrolyte naturally provides lithium ions that are inserted into the anode during charging cycles, eliminating the need for external lithium metal sources and simplifying the manufacturing process
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
This method enhances energy density and power density by up to 100% and reduces manufacturing costs, achieving comparable performance to conventional methods in a fraction of the time, with improved safety and simplicity.
Implementation Method 1
compressing a lithium ion capacitor to insert lithium ions into the anode carbon structure
Implementation Method 2
conditioning through fast charging and discharging, which redistributes the lithium ions throughout the anode carbon structure
Data Source
AI summary
A method for pre-doping a lithium ion capacitor, including:compressing a lithium ion capacitor of the formula:C/S/A/S/C/S/A/S/C,where:/A/ is an anode coated on both sides with an anode carbon layer, and each anode carbon layer is further coated with lithium composite powder (LCP) layer;C/ is a cathode coated on one side with a layer of an cathode carbon mixture; andS is a separator; anda non-aqueous electrolyte; andconditioning the resulting compressed lithium ion capacitor, for example, at a rate of from C/20 to 4C, and the conditioning redistributes the impregnated lithium as lithium ions in the anode carbon structure. Also disclosed is an carbon coated anode having lithium composite powder (LCP) layer compressed on the carbon coated anode.