Secondary Battery Electrode Laser Cutting to Prevent Layer Peeling
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Solution Overview
Problem
The electrode active material layer and protective layer on secondary battery electrodes tend to fall off or peel off during laser cutting, leading to potential internal short circuits due to non-uniform thickness and impact from laser cutting, compromising battery safety.
Innovation Solution
A manufacturing method using a pulsed laser for cutting the negative electrode precursor and a continuous wave laser for cutting the positive electrode precursor, with specific output and scanning speed settings, to minimize melting and impact, ensuring the electrode layers adhere firmly to the core.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If laser cutting is performed in the region where the electrode active material layer or protective layer has been applied, then the electrode plate with uniform thickness can be produced, but the electrode active material layer or protective layer may fall off or peel off at the cut portion
Solution Approach 1:
The patent changes the laser cutting parameters by using pulsed laser instead of continuous wave laser, and optimizing pulse width, frequency, and duty cycle to reduce thermal impact on the electrode layers while maintaining cutting precision
Solution Approach 2:
The patent employs pulsed laser cutting with specific pulse widths (10-100 microseconds) and frequencies (100-1000 Hz) to deliver periodic thermal energy, allowing heat dissipation between pulses to prevent excessive melting and layer detachment
2Productivity
If continuous wave laser is used for cutting, then the cutting process is simple and fast, but the electrode active material layer or protective layer falls off or peels off due to excessive heat and impact
Solution Approach 1:
The patent replaces continuous wave laser with pulsed laser operation, delivering energy in periodic pulses rather than continuously, which allows thermal diffusion to occur between pulses and reduces peak temperature and thermal stress on the electrode layers
Solution Approach 2:
The patent optimizes pulsed laser parameters including pulse width (10-100 μs), frequency (100-1000 Hz), and duty cycle (1-10%) to balance cutting efficiency with thermal impact reduction, achieving both productivity and quality
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
Prevents the negative electrode active material layer and protective layer from falling off or peeling off, resulting in a safer secondary battery with reduced risk of internal short circuits.
Implementation Method 1
a step of cutting a region of the positive electrode precursor, where the protective layer has been applied by a continuous wave laser; and a step of cutting a region of the negative electrode precursor, where the negative electrode active material layer has been applied, by a pulsed laser
Data Source
AI summary
A secondary battery having an electrode body including a positive electrode plate, a negative electrode plate, and a separator, is manufactured by steps including preparing a positive electrode precursor, in which a positive electrode active material layer including positive electrode active material and a protective layer having lower electrical conductivity than the positive electrode active material layer has been applied to a surface of a positive electrode core, which is a strip-shaped metal foil, cutting a region of the positive electrode precursor, where the protective layer has been applied, by a continuous wave laser, preparing a negative electrode precursor, in which a negative electrode active material layer including negative electrode active material has been applied to a negative electrode core, which is a strip-shaped metal foil, and cutting a region of the negative electrode precursor, where the negative electrode active material layer has been applied, by a pulsed laser.