Secondary Battery Base-Tab Laser Welding for Heat-Safe Assembly
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Solution Overview
Problem
The existing welding process for secondary battery electrode assemblies can damage the electrode plates due to heat transfer and inefficient space utilization, as bent non-coating portion tabs are used, which affects the battery's performance and efficiency.
Innovation Solution
A secondary battery design that employs laser welding of base tabs to collectors in a surface contact configuration, with back beads protruding to secure a wide and even melting area, improving weldability and reducing heat damage to the separator, and optimizing space utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bent non-coating portion tabs are used for welding, then welding connection is achieved, but heat damages the electrode plate and space utilization deteriorates
Solution Approach 1:
The patent replaces traditional mechanical bending and contact welding with laser welding technology. The laser beam directly melts and fuses the base tab to the current collector without requiring mechanical bending, thereby eliminating heat damage to the electrode plate while achieving reliable welding connection.
Solution Approach 2:
The patent changes the welding method from conventional contact welding to laser welding, altering the thermal parameters and energy distribution. This parameter change allows precise control of heat input, concentrating it only at the welding point rather than transferring heat to the electrode plate, thus improving welding reliability without causing thermal damage.
2Reliability
If bent non-coating portion tabs are used for welding, then welding connection is achieved, but space utilization inside the battery deteriorates
Solution Approach 1:
The patent eliminates the need for mechanical bending of base tabs by using laser welding. This substitution allows the base tabs to remain in their original flat position, optimizing space utilization inside the battery while still achieving reliable welding connection to the current collector.
3Ease of manufacture
If conventional welding process is used, then welding is performed, but weldability is insufficient and manufacturing precision is poor
Solution Approach 1:
The patent replaces conventional welding processes with laser welding, which provides superior weldability and manufacturing precision. The laser technology enables precise control of the welding process, achieving consistent high-quality welds with excellent repeatability and reduced defects.
Solution Approach 2:
The patent utilizes laser welding parameters (energy density, pulse duration, focal point) to achieve optimal weldability and precision. By controlling these parameters, the process achieves deep penetration with narrow heat-affected zones, significantly improving welding quality and ease of manufacture compared to conventional methods.
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 enhances weldability and electrode plate reactivity by dispersing heat evenly through a wider current path, reducing defects and improving space efficiency within the battery.
Implementation Method 1
the first base tab and the second base tab are laser welded to the pair of collectors, respectively
Implementation Method 2
a wide and even melting area may be secured to improve weldability. Therefore, even electrode plate reactivity may be secured through heat generation with a wide current path
Data Source
AI summary
A secondary battery includes: a case; an electrode assembly in the case and comprising a first electrode plate on which a first base tab is located at a first end in a longitudinal direction of the case, a second electrode plate on which a second base tab is located at a second end in the longitudinal direction of the case, and a separator between the first electrode plate and the second electrode plate; and a cap assembly coupled to the case, and comprising a pair of collectors electrically connected to the first base tab and the second base tab, respectively, wherein the first base tab and the second base tab are laser welded to the collectors.