Flow Cell Reducing-Agent Regeneration for Battery Recycling
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Solution Overview
Problem
Current lithium-ion battery recycling processes, particularly electrochemical-based hydrometallurgical methods, face high operational and capital costs due to batch processes with low electrochemical reaction rates and energy inefficiencies, generating waste and relying on excessive reagents.
Innovation Solution
A battery recycling system utilizing an electrochemical flow cell reactor to regenerate a reducing agent independently of a hydrometallurgical process, enabling high conversion rates with forced convective flow and allowing for continuous operation of the stirred-tank reactor at a lower energy consumption rate, reducing capital and operational costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a batch electrochemical process is used to recycle battery materials, then the process can be implemented with existing technology, but the electrochemical reaction rates are poor due to continuously decreasing reactant concentrations and minimal convective flow
Solution Approach 1:
The system pre-prepares fresh electrolyte solution containing reduced species in storage tanks before the electrochemical reaction begins. This preliminary preparation ensures that high-concentration reactants are available throughout the process, maintaining high reaction rates without the concentration depletion problem inherent in batch processes.
Solution Approach 2:
The system implements continuous flow of electrolyte through the electrochemical reactor, constantly replenishing reactants and removing products. This continuous action maintains optimal reaction conditions throughout operation, eliminating the declining reaction rates seen in batch processes where reactant concentrations continuously decrease.
2Productivity
If an electrochemical-based hydrometallurgical process is used, then battery materials can be recycled, but large amounts of energy are consumed and excessive amounts of reagents are required
Solution Approach 1:
The system recovers and recycles the electrolyte solution containing oxidized species back through the electrochemical cell, where it is reduced and returned to the hydrometallurgical reactor. This closed-loop recovery eliminates the need for continuous addition of fresh reagents, significantly reducing reagent consumption while maintaining high recycling efficiency.
Solution Approach 2:
The electrochemical cell automatically regenerates the reducing agents in situ by electrochemically reducing the oxidized species in the electrolyte. This self-service mechanism eliminates the need for external reagent addition and minimizes energy consumption by using electricity to drive the regeneration process efficiently.
3Device complexity
If the electrochemical reactor and hydrometallurgical reactor are coupled, then the process can be integrated, but the reactors cannot operate at independent rates leading to increased operational and capital costs
Solution Approach 1:
The system divides the recycling process into two independent but connected reactors: a hydrometallurgical reactor for leaching and an electrochemical reactor for electrolyte regeneration. Each reactor can be operated at its own optimal rate and conditions, providing operational flexibility while maintaining process integration through the circulation of electrolyte between them.
Solution Approach 2:
The electrolyte solution acts as an intermediary carrier between the two reactors, transporting metal ions from the hydrometallurgical reactor to the electrochemical reactor and returning regenerated reducing agents back to the first reactor. This intermediary mechanism enables independent operation of both reactors while maintaining their functional integration.
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 system achieves efficient recycling of lithium-ion battery materials with reduced energy and reagent consumption, minimizing waste and emissions, and enabling the use of low-cost, low-carbon electrical energy, thereby making lithium-ion battery recycling more sustainable and cost-effective.
Implementation Method 1
an electrochemical flow cell to regenerate a reducing agent
Implementation Method 2
Since the electrochemical reactor effectively employs forced convective flow it enables operation at high conversion rates with minimal overpotential
Implementation Method 3
the second fluid is water, which is oxidized to form molecular oxygen and protons on the anode
Data Source
AI summary
Disclosed is a battery recycling process wherein an electrochemical flow cell reactor is used to regenerate a reducing agent in an efficient manner. The reactor is decoupled from a hydrometallurgical process in which the reducing agent is used to promote the leaching and reduction of used battery materials in a stirred-tank reactor, such that these two potentially continuous reactors can be operated at independent rates. Since the electrochemical reactor effectively employs forced convective flow, it enables operation at high conversion rates with minimal overpotential and can also be preferentially operated when electrical energy is readily available while the stirred-tank reactor can be operated essentially continuously at a relatively low rate, which enables this equipment to be sized for the desired average energy consumption rate. These features reduce the capital and operation costs relative to electrochemical-based hydrometallurgical process systems taught by others.