Negative Electrode Pre-Lithiation via Rolling Composite
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium secondary batteries face issues with initial irreversible phase formation during charging and discharging, leading to reduced efficiency and capacity, particularly due to the volumetric expansion of silicon-based negative electrode active materials.
Innovation Solution
A method of manufacturing a negative electrode composite by dispersing lithium metal powder and a binder in a dispersion medium, coating it on a transfer film, and forming a composite with a metalloid oxide active material layer through rolling, which pre-lithiates the alloy, minimizing the formation of irreversible phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If carbon is coated on silicon-based material to form composite, then battery life is improved and volumetric expansion is reduced, but initial charging/discharging efficiency is lowered due to formation of irreversible phases
Solution Approach 1:
The patent applies preliminary action by pre-compositing lithium with metalloid oxide before battery assembly. This advance preparation ensures that lithium is already present in the negative electrode active material, so when the battery undergoes initial charging/discharging, the lithium is already in its proper state and does not form irreversible phases, thereby maintaining high initial efficiency while still providing the protective benefits of the composite structure
Solution Approach 2:
The patent converts the harmful effect of volumetric expansion and irreversible phase formation into a benefit by pre-forming the lithium-composite structure. The initial charging/discharging process, which normally creates harmful irreversible phases, is transformed into a beneficial pre-lithiation step that actually improves overall battery performance by eliminating future capacity loss from irreversible phase formation
2Productivity
If metalloid oxide and lithium are pre-composited to reduce irreversible phases, then initial efficiency is increased, but manufacturing complexity increases
Solution Approach 1:
The patent merges the lithium preparation and metalloid oxide composite formation into a single integrated process step. By dispersing lithium metal powder together with metalloid oxide particles in the negative electrode active material layer during the coating process, the patent combines what would otherwise be separate complex steps into one straightforward manufacturing operation, thereby achieving pre-lithiation without significantly increasing manufacturing complexity
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 approach enhances the initial efficiency of the negative electrode by reducing the formation of lithium oxide and lithium metal oxide during the first charge-discharge cycle, thereby improving the battery's capacity retention and safety.
Implementation Method 1
dispersing a lithium metal powder and a binder in a dispersion medium to prepare a lithium dispersion
Implementation Method 2
coating the lithium dispersion on one side of a transfer film to form a coating layer of the lithium metal powder
Implementation Method 3
bringing the coating layer of the lithium metal powder into contact with a negative electrode active material layer of the negative electrode, followed by rolling to form a composite
Implementation Method 4
lithium and metalloid oxide can be pre-lithiated simultaneously with the operation of the battery, thereby minimizing the formation of irreversible phases
Data Source
AI summary
A method for manufacturing a negative electrode for a lithium secondary battery. A negative electrode for a lithium secondary battery is manufactured while forming a composite of lithium metal and a negative electrode active material through a rolling process In the case of the lithium secondary battery to which the negative electrode containing such a composite is applied, when the battery starts to operate, the negative electrode active material is pre-lithiated, and thus charging/discharging process proceeds in the state where the lithium alloy is already formed on the negative electrode, thereby showing an effect of reducing initial irreversible phases.