External Terminal Welding Structure for Prismatic Battery Cells
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Solution Overview
Problem
Existing battery cell welding techniques often result in internal shorts and safety issues due to foreign materials introduced during the welding process, which also decrease energy density by creating empty spaces within the cell.
Innovation Solution
A prismatic battery cell design with a terminal and current collector welded externally, utilizing a protrusion and terminal partition material to control the welding process and minimize foreign material ingress, while a current collector position fixing plate ensures precise positioning during welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If internal welding is performed within the battery cell housing, then the welding connection can be formed, but foreign materials are introduced causing internal shorts and safety issues
Solution Approach 1:
The welding operation is extracted from the internal cell environment and performed externally on the terminal structure. The current collector protrudes through the terminal partition material to allow welding to occur outside the sealed housing, eliminating the source of foreign material contamination while maintaining welding connection reliability.
Solution Approach 2:
The terminal partition material acts as an intermediary structure that separates the internal cell environment from the external welding zone. It allows the current collector to pass through while blocking foreign materials from entering the cell interior during the welding process, thus protecting against internal shorts.
2Reliability
If internal welding is performed within the battery cell housing, then the terminal connection can be established, but empty spaces are created decreasing energy density
Solution Approach 1:
The welding operation is moved to the external terminal structure, eliminating the need for internal empty spaces that would be required to accommodate welding equipment and materials. This extraction of the welding process from the cell interior prevents energy density reduction while maintaining terminal connection stability.
3Object-affected harmful factors
If external welding is performed on the terminal structure, then foreign material ingress is prevented, but precise positioning of the current collector is required
Solution Approach 1:
The current collector is pre-positioned within the terminal structure before the welding operation. The protrusion through the terminal partition material is prepared in advance to ensure correct alignment and positioning, eliminating positioning difficulties during the actual welding process while maintaining the benefits of external welding.
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 prevents internal shorts and increases energy density by ensuring a secure, external weld that maintains the structural integrity and efficiency of the battery cell.
Implementation Method 1
The terminal partition material is welded to the current collector from an area external to the cell and through the first opening
Data Source
AI summary
A cell that includes a housing and a current collector with a protrusion. The cell also includes a cap assembly that closes the housing, the cap assembly including a terminal with a first opening, a second opening, and a terminal partition material separating the second opening from the first opening. The current collector is placed in the second opening and welded to the terminal at the first opening to form a terminal-to-current collector weld at an external area of the cell.