Counter-Rotating Blade Separator Cutting for Battery Electrode Assembly
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Solution Overview
Problem
Existing methods for assembling electrodes, particularly for electrical energy storage devices like lithium batteries, face low productivity and risk of damaging thin, flexible separators during assembly, especially when dealing with electrodes of relatively limited length.
Innovation Solution
A method and apparatus that use counter-rotating blades to cut a separator along a transverse cutting line in a portion between adjacent electrodes, allowing continuous material processing and high productivity, while maintaining the stability and rigidity provided by the electrodes to prevent damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a blade with linear motion cuts a separator with a series of transverse cuts, then the separator can be divided into segments, but the productivity is low when assembling electrodes of limited length due to short cutting steps and inertia of moving masses
Solution Approach 1:
The patent replaces the linear motion cutting system with a rotary cutting system where the blade rotates to perform multiple cuts in sequence. This dynamic approach allows the separator to be fed continuously at high speed while the rotating blade performs cuts at optimized intervals, resolving the contradiction between maintaining high feed speed and achieving adequate cutting frequency for limited-length electrodes.
Solution Approach 2:
The rotary blade performs cuts at periodic intervals as it rotates, with each rotation providing a series of transverse cuts. This periodic action allows the system to maintain continuous high-speed separator feeding while ensuring cuts are made at the necessary frequency, thereby improving productivity without sacrificing feed speed.
2Productivity
If the separator is pulled to advance during assembly, then continuous material processing is enabled, but the thin, flexible separator can easily tear off if pulled too much
Solution Approach 1:
The patent performs the cutting action before the separator is fully advanced through the assembly line. By pre-cutting the separator in a controlled manner while it is still supported by the assembly structure, the system enables continuous feeding without requiring excessive pulling forces that would damage the thin separator material.
Solution Approach 2:
The rotary cutting system acts as an intermediary mechanism that divides the separator into segments without requiring the separator to be pulled excessively. The rotating blade provides a controlled cutting action that separates the material cleanly, allowing continuous processing while maintaining separator integrity by avoiding high tensile stresses.
3Manufacturing precision
If transverse cuts are made frequently for limited length electrodes, then assembly precision is improved, but the inertia of moving masses prevents working with high feed speeds
Solution Approach 1:
The system transitions from linear motion with frequent stopping and starting to continuous rotary motion. The rotating blade maintains constant angular velocity, providing consistent cutting precision through dynamic balance and reduced mechanical shock, while allowing the separator to be fed at high continuous speeds without the inertia limitations of reciprocating linear motion.
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
Enables the assembly of electrodes of limited lengths with high productivity and efficiency, producing high-quality electrical energy storage devices with reduced risk of separator damage, and provides a constructively simple and economical solution.
Implementation Method 1
cutting the separator by a pair of counter-rotating blades along a cutting line which is transverse to a feed direction of the separator
Data Source
AI summary
In a method and apparatus for assembling electrodes, in order to produce electrical energy storage devices, in particular lithium batteries, the electrodes are placed one after the other at a mutual distance on a separator which advances along a feeding path, then the separator is cut by a pair of counter-rotating blades along a cutting line perpendicular to the feeding direction of the separator, said cutting line being arranged in a separator portion without electrodes and comprised between two adjacent electrodes; the method and apparatus allow the assembly of electrodes of limited length with high productivity.