Lithium-Ion Battery Anode Melt Processing Without Solvent Evaporation
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Solution Overview
Problem
Existing manufacturing processes for lithium-ion battery anodes face challenges such as low active material mass fraction in polymer compositions, leading to insufficient capacity and mechanical cohesion, as well as environmental and safety issues related to solvent use and drying requirements.
Innovation Solution
A melt processing method without solvent evaporation, using a crosslinkable elastomer matrix, electrically conductive filler, and non-volatile organic compounds to achieve a polymer composition with an active material mass fraction greater than 85%, ensuring high-performance anodes with enhanced mechanical strength and reduced environmental hazards.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the mass fraction of active material in the anode polymer composition is increased to at least 85%, then the capacity of the lithium-ion battery is improved, but the viscosity of the polymer mixture becomes very high, leading to overheating risk and loss of mechanical cohesion
Solution Approach 1:
The patent changes the physical and chemical parameters of the polymer mixture by introducing a specific solvent system (mixing volatile and non-volatile solvents) and controlling the composition ratios. This allows achieving 85%+ active material content while maintaining processability and mechanical properties through optimized solvent interaction and evaporation characteristics
Solution Approach 2:
The patent uses a composite approach by combining multiple solvents (volatile and non-volatile) in specific ratios, and later replacing them with ionic liquids. This composite solvent system enables the high active material content mixture to maintain appropriate viscosity and mechanical cohesion during processing and operation
2Ease of manufacture
If conventional manufacturing processes using organic solvents are used, then the anode can be manufactured, but large amounts of toxic and inflammable solvents must be evaporated, creating environmental and safety issues
Solution Approach 1:
The patent fundamentally changes the solvent parameter from conventional organic solvents to ionic liquids, which have negligible vapor pressure. This eliminates the need for large-scale solvent evaporation while maintaining the manufacturing process effectiveness, thereby resolving the environmental and safety issues associated with toxic and inflammable solvent evaporation
Solution Approach 2:
The patent replaces the traditional solvent evaporation mechanism (thermal removal of volatile solvents) with an alternative approach using ionic liquids that remain in the system or can be removed through non-evaporative means, thereby eliminating the harmful evaporation step entirely
3Object-affected harmful factors
If aqueous solvents are used to manufacture anodes, then the manufacturing process is safer, but the anode must be very thoroughly dried to remove traces of water, as water limits the useful lifetime of lithium storage batteries
Solution Approach 1:
The patent introduces ionic liquids as an intermediary substance that serves as a safe alternative to both organic and aqueous solvents. Ionic liquids provide the safety benefits of non-flammability during manufacturing while leaving no harmful residues that would affect battery lifetime, as they can be completely removed or replaced by the battery electrolyte without requiring extensive drying
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
The method results in high-performance lithium-ion battery cells with improved mechanical strength and increased active material capacity, while eliminating the need for solvent evaporation and reducing water content, thereby enhancing battery performance and safety.
Implementation Method 1
a crosslinking step of this polymer mixture, in order to obtain a polymer composition
Implementation Method 2
a melt processing step, without solvent evaporation, of an active material and additives comprising a binder and a non-volatile organic compound
Implementation Method 3
processes for manufacturing anodes for lithium-ion batteries using melt processing techniques (for example extrusion)
Data Source
AI summary
An anode usable in a cell of a lithium-ion battery comprising an electrolyte based on a lithium salt and a non-aqueous solvent, to a process for manufacturing this anode and to a lithium-ion battery having one or more cells incorporating this anode. This anode is based on a polymer composition, obtained by melt processing and without solvent evaporation, that is the product of a hot compounding reaction between an active material and additives having a polymer binder and an electrically conductive filler. The binder is based on at least one crosslinked elastomer and the additives furthermore include at least one non-volatile organic compound usable in the electrolyte solvent, the composition advantageously includes the active material in a mass fraction greater than or equal to 85%.