Electrode Scrap Recycling by Dry Milling and Sieving

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Solution Overview

Problem

The recycling of valuable metals from lithium secondary battery electrode scraps is inefficient, leading to high costs and environmental concerns due to the complexity and additional expenses of conventional methods, which often require chemical processes and result in performance degradation.

Innovation Solution

A method involving dry milling and sieving of electrode scraps to separate active material layer flakes from current collector fragments, using a series of sieves with decreasing mesh sizes to obtain reusable particles, which can be directly used to fabricate new electrodes without additional treatments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If conventional chemical recycling methods are used to recover active material from electrode scraps, then metal extraction can be achieved, but the process complexity increases and performance degradation occurs

Engineering Contradiction:
Improveactive material recoveryVSAvoidrecycling process complexity
Core Design Contradiction:
Loss of substanceVSDevice complexity

Solution Approach 1:

The patent replaces chemical recycling methods with a purely mechanical approach using dry milling and classification equipment. The mill breaks down electrode scraps into particles, and the classifier separates active material particles from current collector fragments based on size differences, eliminating the need for chemical processes while maintaining recovery efficiency

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The recycling process is divided into two distinct stages: dry milling to fragment the electrode scrap material, and classification to separate active material from current collector based on particle size. This segmentation allows each stage to be optimized independently and simplifies the overall process

Inventive Principle:
Principle #1Segmentation

2Loss of substance

If conventional chemical recycling methods are used, then active material can be recovered, but additional costs and performance degradation occur

Engineering Contradiction:
Improveactive material recoveryVSAvoidelectrode performance
Core Design Contradiction:
Loss of substanceVSReliability

Solution Approach 1:

The patent replaces chemical recycling methods with a purely mechanical approach using dry milling and classification equipment. The mill breaks down electrode scraps into particles, and the classifier separates active material particles from current collector fragments based on size differences, eliminating the need for chemical processes while maintaining recovery efficiency

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent controls particle size parameters through the classification process to ensure that active material particles are separated at optimal sizes that maintain their electrochemical performance. By adjusting classification mesh sizes and cutting speeds, the process preserves the structural integrity and performance characteristics of the recovered active material

Inventive Principle:
Principle #35Parameter changes

3Ease of manufacture

If simple dry milling is used without classification, then processing is simplified, but separation of active material from current collector is incomplete

Engineering Contradiction:
Improveprocess simplicityVSAvoidseparation purity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The recycling process is divided into two distinct stages: dry milling to fragment the electrode scrap material, and classification to separate active material from current collector based on particle size. This segmentation allows each stage to be optimized independently and simplifies the overall process

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent controls particle size parameters through the classification process to ensure that active material particles are separated at optimal sizes that maintain their electrochemical performance. By adjusting classification mesh sizes and cutting speeds, the process preserves the structural integrity and performance characteristics of the recovered active material

Inventive Principle:
Principle #35Parameter changes

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 approach simplifies the recycling process, reduces costs, and maintains the performance of lithium secondary batteries by allowing the direct reuse of active material layer flakes without altering their composition, thus enhancing recycling ratios and electrode properties.

Implementation Method 1

a pin-mill, which rotates in a counter-direction to the rotor, is provided between the rotor and the stator

Methodology Applied
Scientific EffectMechanical impact and friction: Friction

Implementation Method 2

screening active material layer flakes from current collector fragments in the milled products by sieving the milled products

Methodology Applied
Scientific EffectPhysical filtration by mesh size: Filter (physical)

Data Source

PatentEP3940872B1Method for recycling electrode scraps, and method for manufacturing electrode by using same
Publication Date: 2023.08.30 LG ENERGY SOLUTION LTD
  • EP3940872B1 patent drawingFigure 1
  • EP3940872B1 patent drawingFigure 2
  • EP3940872B1 patent drawingFigure 3

AI summary

Provided are a reuse method of electrode scrap and a method of fabricating a recycled electrode using the same. The reuse method of electrode scrap of the present disclosure includes (a) dry milling electrode scrap remaining after punching an electrode sheet including an active material layer on a current collector to obtain milled products; and (b) screening active material layer flakes from current collector fragments in the milled products by sieving the milled products, and collecting the screened active material layer flakes to obtain reusable particles.