Electrochemical Generator Opening in Inert Liquid for Safe Discharge
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Solution Overview
Problem
Current methods for recycling lithium-based electrochemical systems, such as batteries and accumulators, face challenges in safely opening and discharging them due to risks of ignition and explosion, particularly when partially charged or damaged, and require expensive or difficult-to-implement treatments like controlled atmospheres and cryogenic processes.
Innovation Solution
A method involving immersing the electrochemical generator in an inert liquid solution with a cutting element of controlled electrical resistance to safely open and discharge the system, using a redox species to react with lithium or sodium electrodes, thereby controlling the discharge and preventing violent reactions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional grinding methods are used to open electrochemical generators, then productivity is improved, but safety deteriorates due to risks of ignition and explosion
Solution Approach 1:
The patent introduces an inert liquid medium as an intermediary substance between the electrochemical generator and the environment. This liquid allows the generator to be opened and ground while preventing direct contact with oxygen and moisture, thereby eliminating ignition risks. The cutting element operates within this liquid medium, enabling safe high-speed processing without compromising safety.
Solution Approach 2:
The patent creates an inert environment by immersing the electrochemical generator in an inert liquid medium during the opening and grinding process. This liquid atmosphere replaces air, preventing oxidation reactions and eliminating the risk of ignition from sparks generated during grinding, thus allowing high-productivity operations without safety compromises.
2Reliability
If controlled atmosphere methods are used to prevent ignition, then safety is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses a liquid medium (hydraulic approach) instead of complex gas-based controlled atmosphere systems. The inert liquid naturally provides the protective environment without requiring sophisticated gas flow control, sealing systems, or atmospheric monitoring equipment, thereby achieving safety with simpler device architecture.
Solution Approach 2:
The patent simplifies the inert atmosphere concept by using an inert liquid medium instead of complex gaseous systems. The liquid inherently provides oxygen exclusion and safety without requiring additional control mechanisms, sensors, or complex infrastructure, reducing device complexity while maintaining high safety standards.
3Reliability
If cryogenic treatments are used to make cells safe, then safety is improved, but energy consumption and cost increase
Solution Approach 1:
The patent changes the fundamental parameter of the protective medium from extreme cold (cryogenic) to ambient temperature inert liquid. This parameter change eliminates the need for energy-intensive cooling systems while maintaining safety, as the inert liquid provides protection through chemical inertness rather than temperature effects.
Solution Approach 2:
The patent avoids cryogenic phase transitions (freezing) by using an inert liquid medium at ambient temperature. This eliminates the energy consumption associated with cooling cells to cryogenic temperatures and maintaining those temperatures during processing, while still achieving safe opening conditions.
4Productivity
If electrochemical generators are ground while charged, then productivity is improved, but harmful factors increase due to sparks and ignitions
Solution Approach 1:
The inert liquid medium acts as an intermediary that suppresses harmful sparks and ignitions generated during grinding of charged electrochemical generators. The liquid absorbs and quenches sparks immediately upon formation, preventing ignition while allowing continuous high-speed grinding operations without interruption for discharging.
Solution Approach 2:
The inert liquid creates an oxygen-free environment that prevents sparks from igniting during the grinding of charged generators. This allows productivity to be maximized by grinding cells in their charged state without generating harmful ignition risks, as the inert atmosphere eliminates the combustion triangle.
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 method allows for safe and efficient opening and discharge of electrochemical generators, reducing the risk of explosions and thermal runaway, and is compatible with high work rates and industrial-scale processing, while minimizing environmental and economic costs.
Implementation Method 1
The inert liquid solution absorbs the thermal energy and heat generated during cutting and discharge, preventing thermal runaway
Implementation Method 2
a method involving immersing the electrochemical generator in an inert liquid solution with a cutting element of controlled electrical resistance to safely open and discharge the system, using a redox species to react with lithium or sodium electrodes
Data Source
AI summary
A method for opening an electrochemical generator comprising a negative electrode containing lithium or sodium and a positive electrode optionally containing lithium or sodium, the method including the following successive steps: a) immersing the electrochemical generator in a solution comprising an inert liquid and, optionally, a so-called oxidising redox species able to be reduced on the negative electrode so as to discharge the electrochemical generator, b) opening the electrochemical generator, in the solution, with a cutting element having an electrical resistance of between 1 mΩ and 1 kΩ, and preferably between 5 mΩ and 100Ω.