Lithium Iron Phosphate Battery Recycling With Low-Temperature Heat Treatment
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Solution Overview
Problem
Existing waste lithium-ion battery recycling methods are inefficient, costly, and environmentally harmful due to high-temperature processes that introduce impurities and require complex steps, leading to low recovery rates of valuable lithium iron phosphate powder.
Innovation Solution
A low-temperature heat-treatment method is employed to recover lithium iron phosphate powder by heating waste batteries to 200-400°C, maintaining the temperature, and forcibly exhausting gases to minimize impurities, allowing direct reuse of the powder in new batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-temperature heating is used to remove organic compounds and polymer components, then the organic components are effectively removed, but the process becomes complex, time-consuming, and introduces impurities that lower extraction rates
Solution Approach 1:
The patent changes the temperature parameter from conventional high-temperature heating to low-temperature heating (specifically 100-200°C), which fundamentally alters the removal mechanism from thermal decomposition to selective dissolution. This parameter change simplifies the process by eliminating the need for complex high-temperature equipment while effectively removing organic components through their solubility characteristics at lower temperatures.
Solution Approach 2:
The patent replaces the mechanical/thermal system (high-temperature heating) with a chemical system (selective dissolution using solvents). Instead of using heat to decompose and remove organic components, the method uses chemical solvents to selectively dissolve and remove organic materials, thereby simplifying the equipment requirements and reducing process complexity.
2Reliability
If high-temperature heating is used to remove organic compounds, then organic components are removed, but valuable components are lost and extraction rate decreases
Solution Approach 1:
By changing the temperature parameter to a lower range (100-200°C), the patent prevents thermal decomposition of valuable lithium iron phosphate and other inorganic components that would occur at high temperatures. The lower temperature selectively targets organic components for removal while preserving valuable materials.
Solution Approach 2:
The patent converts the typical approach of using high heat (which causes damage to valuable components) into a beneficial low-temperature process. The low temperature, which would normally be insufficient for complete organic removal, becomes advantageous when combined with selective solvent dissolution, achieving organic component removal without damaging valuable materials.
3Loss of substance
If conventional dry smelting process is used, then valuable metals can be extracted, but the process requires many devices and complicated steps making it less economical
Solution Approach 1:
The patent merges multiple conventional process steps into a single integrated low-temperature treatment step. Instead of separate discharge, dismantling, grinding, and extraction steps requiring multiple devices, the invention combines organic component removal and valuable metal recovery into one simplified process using low-temperature heating followed by selective dissolution, reducing both device count and process steps.
Solution Approach 2:
By changing the temperature parameter to low-temperature range, the patent enables a single-step process that achieves both organic component removal and valuable metal recovery, eliminating the need for subsequent high-temperature smelting and complex extraction steps required in conventional processes.
4Reliability
If high-temperature heating is used, then organic components are removed, but the discharged powder contains large amounts of impurities requiring regrinding and strong acid treatment
Solution Approach 1:
By changing the temperature to a lower range (100-200°C), the patent prevents the formation of impurities and aggregation that occur during high-temperature heating. The low-temperature process maintains the powder in a fine, pure state suitable for direct use without requiring additional grinding or acid treatment steps.
Solution Approach 2:
The patent replaces high-temperature thermal processing with low-temperature chemical dissolution, which selectively removes organic components without causing the side effects (impurity formation, powder aggregation) associated with high-temperature heating, thereby maintaining high powder purity.
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 enhances recycling efficiency and reduces environmental impact while producing high-quality lithium iron phosphate powder for new batteries without additional processing, thus increasing economic viability and reducing environmental harm.
Implementation Method 1
increasing the temperature inside the heat-treatment furnace to a range of 200° C. to 400° C., maintaining the increased temperature to heat treat the object to be heat-treated
Data Source
AI summary
A method for recycling a waste lithium-ion secondary battery includes (a) loading an object to be heat-treated into a heat-treatment furnace, the object being at least a part of a waste lithium-ion secondary battery in which lithium iron phosphate powder is a positive electrode material, and including the positive electrode material, (b) increasing the temperature inside the heat-treatment furnace to a range of 200° C. to 400° C., (c) maintaining the increased temperature to heat treat the object to be heat-treated, and (d) discharging first powder produced after the completion of the heat treatment, wherein the first powder includes recycled lithium iron phosphate powder.