Lithium Predoping via Slurry Mixing for Battery Electrodes

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Solution Overview

Problem

Current lithium predoping methods for lithium ion batteries and capacitors are complex, time-consuming, and inefficient, particularly for batteries with multiple thin electrodes or wound structures, and often result in incomplete lithium doping and increased internal resistance.

Innovation Solution

A method involving the mixing of a lithium-dopable material and lithium metal in the presence of a solvent to predope the material during electrode production, eliminating the need for electrochemical means and simplifying the production process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a porous current collector method is used for lithium predoping, then lithium doping can be performed in the cell assembly, but the production process becomes complex and time-consuming with incomplete doping uniformity

Engineering Contradiction:
Improvepredoping process simplicityVSAvoidproduction efficiency
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

Lithium predoping is performed during the electrode manufacturing process before cell assembly, rather than during cell assembly. The lithium metal powder is mixed with the active material in advance, achieving predoping in the electrode production stage and eliminating the need for separate predoping steps during cell assembly.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The lithium predoping process is merged with the electrode manufacturing process. The mixing of lithium metal powder with active material during electrode slurry preparation combines two previously separate operations (electrode fabrication and lithium predoping) into a single integrated process, simplifying production and improving efficiency.

Inventive Principle:
Principle #5Merging (Combining)

2Manufacturing precision

If lithium metal foil is laminated to electrodes for predoping, then uniform lithium doping is achieved, but handling and production become complicated for batteries with multiple thin electrodes or wound structures

Engineering Contradiction:
Improvelithium doping uniformityVSAvoidproduction process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The form of lithium source is changed from thin lithium metal foil to lithium metal powder. This parameter change allows lithium to be easily mixed with active material during electrode fabrication, achieving uniform distribution and doping without the handling complexities associated with thin foil lamination in multi-layer or wound battery structures.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If electrochemical predoping method is used, then lithium doping can be performed, but the process requires taking the electrode out of the electrochemical system and becomes impractical for mass production

Engineering Contradiction:
Improvelithium doping effectivenessVSAvoidpractical applicability
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The electrochemical predoping method is replaced with a mechanical mixing approach. Instead of using electrochemical cells and electrical currents to achieve lithium doping, lithium metal powder is mechanically mixed with active material during electrode fabrication, achieving predoping through physical mixing rather than electrochemical reactions.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Reliability

If existing predoping methods are used, then lithium doping is achieved, but production time is extended and internal resistance increases due to incomplete doping

Engineering Contradiction:
Improvelithium doping completenessVSAvoidproduction time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

Lithium predoping is performed during electrode manufacturing before cell assembly and activation. By incorporating lithium metal powder into the active material during the slurry preparation stage, the doping process is completed in advance, eliminating the need for extended aging or activation periods required by conventional methods.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The lithium predoping process is integrated continuously into the electrode manufacturing workflow. The mixing of lithium metal powder with active material occurs during normal electrode fabrication operations, maintaining continuous production flow without interrupting or extending the manufacturing cycle.

Inventive Principle:
Principle #20Continuity of useful action

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 allows for uniform and efficient lithium doping, reducing production time and avoiding issues with thin lithium metal handling, while enabling the mass production of predoped electrodes for use in lithium ion batteries and capacitors.

Implementation Method 1

mixing a material capable of being doped with lithium and lithium metal together in the presence of a solvent

Methodology Applied
Scientific EffectChemical reaction: Chemical Bonding

Data Source

PatentEP2605316B8Method for lithium predoping, method for producing electrodes, and electric energy storage device using these methods
Publication Date: 2019.01.23 KRI INC

AI summary

A predoping technique considered as highly practicable is an electrochemical method in which predoping is performed by assembling a battery such that an active material (electrode) and lithium are brought into direct contact with each other or short-circuited therebetween via an electric circuit, and by filling an electrolytic solution in the battery. However, in this case, much time is required, and there are problems such as the handling and the thickness accuracy of an extremely thin lithium metal foil that is not greater than 30 µm thick. By mixing a lithium-dopable material and lithium metal together in the presence of a solvent, such problems can be solved.