Battery Cell Terminal Structure for External Laser Welding
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Solution Overview
Problem
Ultrasonic welding of electrode terminals to current collectors in battery cells can generate foreign substances like fumes or spatter, causing defects, damaging the electrode assembly, and affecting the electrical connection stability and weldability.
Innovation Solution
A battery cell design with a protrusion on the connection terminal welded externally to the electrode terminal, ensuring the thickness of the connection terminal is equal to or greater than the electrode terminal, and using laser-beam welding to prevent foreign substance generation and reduce welding heat damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If ultrasonic welding is performed through the hollow portion of the electrode assembly while the electrode assembly is inserted into the cell case, then the current collector and electrode terminal can be electrically connected, but welding foreign substances such as fumes or spatter are formed in the battery cell causing defects
Solution Approach 1:
The patent inverts the welding location from inside the cell case to outside the cell case. The protrusion of the connection terminal extends outward from the cell case, allowing welding to be performed externally. This inversion eliminates the generation of welding foreign substances inside the battery cell while maintaining electrical connection stability between the current collector and electrode terminal.
2Reliability
If ultrasonic welding is performed inside the cell case, then electrical connection can be achieved, but the electrode assembly is damaged by welding heat
Solution Approach 1:
The patent extracts the welding operation from the internal environment of the cell case and relocates it to the external environment. By extending the protrusion of the connection terminal outside the cell case, the welding process is separated from the sensitive electrode assembly inside, allowing electrical connection to be achieved without exposing the electrode assembly to welding heat damage.
3Ease of manufacture
If the connection terminal has sufficient thickness to withstand welding heat, then weldability is improved, but the device complexity increases
Solution Approach 1:
The patent adds a spatial dimension to the connection terminal by creating a protrusion that extends outward from the cell case. This dimensional change allows the terminal to have sufficient thickness for weldability at the welding location while maintaining a compact overall structure. The protrusion provides the necessary material volume for welding without increasing the internal complexity within the cell case.
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 foreign substance formation, enhances electrical connection stability, improves weldability and working speed, and reduces damage to the electrode assembly by minimizing heat exposure.
Implementation Method 1
the protrusion is coupled to the electrode terminal by welding performed on an outer side of the cell case in a state of being inserted and coupled to the coupling groove
Data Source
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AI summary
A battery cell includes a cell case including a sidewall and a top plate having a through-hole formed therein; an electrode terminal coupled to the through-hole and having a coupling groove formed in a bottom portion; an electrode assembly; and a first current collector electrically connecting the electrode terminal to the electrode assembly, wherein the first current collector includes a connection terminal having a protrusion inserted and coupled to the coupling groove, wherein the protrusion is coupled to the electrode terminal by welding performed on an outer side of the cell case, and wherein, in a welded region where the protrusion and the electrode terminal are welded, a thickness of the connection terminal has a value equal to or greater than that of a thickness of the electrode terminal.