Secondary Battery Tab Laser Welding With Optical Quality Feedback
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Solution Overview
Problem
Existing welding methods for secondary batteries, such as ultrasonic welding, face challenges in maintaining consistent welding quality, particularly in ultra-thin areas, due to operator dependence and the risk of penetration defects, which are difficult to inspect and verify.
Innovation Solution
A laser welding method and apparatus that uses controlled pulse oscillation of a laser beam to fusion-bond electrode substrate tabs to uncoated regions, forming specific welding patterns and employing a photodiode sensor to monitor welding quality in real-time, minimizing defects and ensuring strong bonding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultrasonic welding is used for secondary batteries, then welding can be performed on electrode substrate tabs, but welding quality consistency deteriorates in ultra-thin areas due to operator dependence and penetration defects
Solution Approach 1:
The patent replaces ultrasonic welding (mechanical vibration-based) with laser welding (optical energy-based). The laser beam irradiates the welding portion to melt and fuse the electrode substrate tab to the uncoated region, eliminating operator dependence and providing consistent welding quality. The laser parameters (power, pulse width, frequency) are precisely controlled to prevent penetration defects in ultra-thin areas.
Solution Approach 2:
The patent incorporates a sensor that detects light reflected from the welding portion in real-time during the welding process. The controller compares the sensor output with a preset reference value to determine welding quality, providing immediate feedback to ensure consistent welding results and detect defects as they occur.
2Strength
If laser welding is applied to ultra-thin areas, then welding strength can be improved, but penetration defects may occur if not properly controlled
Solution Approach 1:
The patent uses pulsed laser welding instead of continuous laser welding. The laser beam is irradiated in periodic pulses with controlled width and frequency, allowing the material to cool between pulses and preventing excessive heat accumulation that would cause penetration defects. This periodic action maintains welding strength while avoiding harmful overheating.
Solution Approach 2:
The patent dynamically adjusts laser parameters (power, pulse width, frequency, duty cycle) based on the specific welding conditions and material thickness. The controller modifies these parameters in real-time to optimize welding strength while preventing penetration defects, making the process adaptable to different ultra-thin area requirements.
3Manufacturing precision
If real-time monitoring is implemented during welding, then welding quality can be ensured, but device complexity increases
Solution Approach 1:
The patent uses a relatively simple optical feedback system where a sensor detects light reflected from the welding portion. The controller compares this signal with a preset reference value to determine welding quality. This straightforward feedback mechanism provides effective real-time monitoring without introducing excessive system complexity.
Solution Approach 2:
The welding process itself generates the monitoring signal through light reflection from the welding portion. The system uses the inherent optical properties of the welding area rather than requiring complex external sensing mechanisms, allowing the process to monitor itself with minimal additional complexity.
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 laser welding method enhances welding strength and reduces defects in ultra-thin areas by controlling laser output and using real-time monitoring, thereby improving the overall welding quality and reliability.
Implementation Method 1
irradiating a first laser beam to laser-weld a first electrode substrate tab onto a first electrode uncoated region
Implementation Method 2
irradiating a first laser beam to laser-weld a first electrode substrate tab onto a first electrode uncoated region
Implementation Method 3
a sensor on one side of the main body, the sensor being configured to detect a light reflected from a welding portion
Implementation Method 4
The sensor may be a photodiode sensor
Data Source
AI summary
Disclosed is a laser welding method for a secondary battery, in which a first electrode substrate tab and a second electrode substrate tab are laser-welded onto a first electrode uncoated region of a first electrode plate and a second electrode uncoated region of a second electrode plate, respectively, wherein the first electrode substrate tab and the second electrode substrate tab are fusion-bonded with a laser beam so as to have a preset welding pattern at welding portions thereof.