Laser Welding Grid to Electrode Tab in Secondary Batteries
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Solution Overview
Problem
Existing methods for connecting a grid to an electrode tab in secondary batteries, such as ultrasonic welding and riveting, often result in overheating, deformation, or require multiple processes, leading to reduced productivity and increased resistance, especially in high-capacity batteries.
Innovation Solution
A connecting structure and method using laser welding with a predetermined pattern, such as linear, zigzag, or wave patterns, to securely join the grid and electrode tab, optionally with a protecting member like polyethylene or polypropylene, and incorporating a simplified process involving a jig for precise alignment and cutting, followed by laser welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultrasonic welding is used to connect the grid and electrode tab, then the connection is achieved, but overheating and vibration are generated which may deform the separator or damage the electrode plate
Solution Approach 1:
The patent replaces ultrasonic welding (mechanical-vibrational system) with laser welding (optical-thermal system). The laser beam directly melts and fuses the grid and electrode tab without generating harmful vibrations, thus maintaining connection reliability while eliminating the harmful mechanical effects of ultrasonic welding.
Solution Approach 2:
The patent changes the welding parameters by using laser welding instead of ultrasonic welding. This involves changing from a mechanical vibration-based process to a concentrated thermal process, adjusting the energy delivery method to achieve better connection quality without harmful side effects.
2Reliability
If riveting is used to connect the grid and electrode tab, then the connection is achieved, but a plurality of processes is required which deteriorates productivity
Solution Approach 1:
The patent merges multiple riveting processes into a single laser welding operation. Instead of requiring separate steps for positioning, hole punching, rivet insertion, and securing, the laser welding process achieves the connection in one continuous operation, significantly improving productivity while maintaining reliable connections.
Solution Approach 2:
The patent replaces the multi-step mechanical riveting process with a single-step laser welding process. This substitution eliminates the need for multiple operations and tool changes, streamlining the manufacturing process and improving overall productivity.
3Quantity of substance
If the number of laminated electrode plates or thickness of current collector foil or electrode tab increases, then the battery capacity increases, but overheating or vibration is generated during welding which may deform the separator or damage the electrode plate
Solution Approach 1:
The patent replaces ultrasonic welding with laser welding to handle thicker materials and higher capacity batteries. The laser welding process provides more controlled heat distribution that can accommodate increased material thickness without generating harmful vibrations, enabling the battery capacity to be increased without compromising connection quality or causing damage to surrounding components.
4Reliability
If existing welding methods are used, then connection is achieved, but resistance is increased which is not suitable for large-capacity high output
Solution Approach 1:
The patent changes the welding parameters and method to achieve lower resistance connections. Laser welding creates a more uniform and controlled melt zone that produces stronger metallurgical bonds with lower contact resistance, making the connection suitable for large-capacity high-output batteries where minimal energy loss is critical.
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 ensures a stable and low-resistance connection, enhancing yield and productivity while minimizing heat generation and process complexity, making it suitable for large-capacity high-output batteries.
Implementation Method 1
a laser welding portion connecting the grid and the electrode tab
Data Source
AI summary
Disclosed is a connecting structure and method between a grid and an electrode tab of a secondary battery, which may ensure stable connection between the grid and the electrode tab of an electrode assembly and allow improved productivity. The connecting structure includes a grid integrally extending from an electrode plate of a secondary battery, an electrode tab connected to the grid, and a laser welding portion connecting the grid and the electrode tab. Also, a connecting method between a grid and an electrode tab of a secondary battery includes (a) fixing the grid with a jig, (b) cutting the grid, and (c) stacking the grid and the electrode tab and connecting the grid and the electrode tab by means of laser welding.