Vacuum Drying Used Lithium Batteries to Remove Electrolyte
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Solution Overview
Problem
Existing methods for treating used lithium batteries face issues such as contamination from plastic degradation products, high hazard potential due to residual electrolyte, formation of toxic compounds like hydrogen fluoride and organofluorine compounds, and inefficient electrolyte recycling, leading to complex and hazardous recycling processes.
Innovation Solution
A method involving drying at low pressure (up to 300 hPa) and temperature (up to 80°C) to remove electrolyte, using a vacuum system connected to a drying device, which allows for simultaneous comminution and drying under vacuum, minimizing the introduction of additional materials and preventing electrochemical reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If batteries are heated before comminution to destroy plastic components, then plastic components are destroyed, but the remaining battery components become contaminated with plastic degradation products
Solution Approach 1:
The invention extracts and removes the electrolyte from the battery components before comminution through vacuum drying. By removing the electrolyte first, the harmful electrochemical reactions are prevented, and subsequent mechanical processing can be performed without generating contaminated degradation products, thus separating the harmful substance removal from the component destruction process
Solution Approach 2:
The invention performs preliminary vacuum drying to remove electrolyte before the comminution step. This preliminary action prevents electrochemical reactions and hazardous substance formation during subsequent mechanical processing, avoiding the contamination problem that occurs when heating is performed before comminution
2Reliability
If crushed material is dusted with deactivation powder to prevent spontaneous combustion, then spontaneous combustion is prevented, but the dusting powder poses exposure risk and the material still possesses high hazard potential
Solution Approach 1:
The invention uses vacuum drying to remove the electrolyte itself, which is the source of hazardous electrochemical reactions. This self-service approach eliminates the need for external deactivation powders, as the removed electrolyte is what would otherwise cause spontaneous combustion, exposure risks, and hazardous atmosphere formation
Solution Approach 2:
The invention creates an inert environment by removing the electrolyte under vacuum conditions. This eliminates the chemical basis for spontaneous combustion and hazardous reactions without introducing foreign deactivation powders, thus preventing combustion while avoiding powder exposure risks
3Productivity
If batteries are processed in a rotary kiln at high temperature to recover active material, then active material is recovered, but large quantities of hydrogen fluoride and organofluorine compounds are produced
Solution Approach 1:
The invention performs preliminary vacuum drying to remove electrolyte before any thermal processing or comminution steps. This preliminary removal of the electrolyte prevents the formation of hydrogen fluoride and organofluorine compounds during subsequent processing, allowing active material recovery without generating these hazardous substances
Solution Approach 2:
The invention changes the operating parameters from high-temperature rotary kiln processing to low-temperature vacuum drying followed by mechanical comminution. This parameter change achieves active material recovery through size reduction and separation rather than thermal decomposition, eliminating the formation of hydrogen fluoride and organofluorine compounds while maintaining productivity
4Productivity
If drying is performed at high temperature to remove electrolyte quickly, then electrolyte removal speed increases, but toxic compounds like hydrogen fluoride and organofluorine compounds are formed
Solution Approach 1:
The invention uses vacuum drying to facilitate electrolyte removal through evaporation at low temperatures. The reduced pressure lowers the boiling point of the electrolyte, allowing rapid evaporation and removal without requiring high temperatures that would decompose the electrolyte into toxic hydrogen fluoride and organofluorine compounds
Solution Approach 2:
The invention changes the drying parameters from high temperature to low temperature combined with reduced pressure. This parameter change maintains fast electrolyte removal speed through enhanced evaporation under vacuum while preventing the thermal decomposition that produces toxic compounds
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 achieves high purity and safety in the comminuted material, enabling efficient recycling with minimal environmental impact and reducing the formation of hazardous compounds, allowing for safe transport and further processing without additional inactivation steps.
Implementation Method 1
a vacuum system connected to the drying device for generating a vacuum of at most 300 hPa in the drying device
Implementation Method 2
drying takes place at a pressure of at most 300 hPa, preferably at least temporarily below 50 hPa, and at a temperature of at most 80 °C
Data Source
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AI summary
The invention relates to a method for treating used lithium batteries (10) comprising the steps of: shredding the batteries (10) to obtain shredded material (24), and inactivating the shredded material (24) by drying to obtain inactivated shredded material (42). According to the invention, drying is carried out at a pressure of no more than 300 hPa and a temperature of no more than 80 °C, and the inactivated shredded material (42) is not filled into a transport container and/or processed further after drying.