Secondary Battery Case-Cover Welding to Cut Dead Space
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Solution Overview
Problem
Existing secondary battery designs face challenges in improving the coupling structure of the case and cover, which affects sealability and increases dead space, thereby reducing battery capacity.
Innovation Solution
A secondary battery design featuring a plate-shaped cover that is coupled to the case with a size smaller than the open surface, where the edge of the case is pressed and laser-welded to ensure close contact, and a hexahedral case with terminals on short sides, incorporating an insulating member to prevent electrical contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If the cover size is reduced to minimize dead space, then battery capacity is improved, but sealability between the case and cover deteriorates
Solution Approach 1:
The edge of the case is pressed in advance to create a protruding surface before the cover is installed. This preliminary deformation of the case edge ensures that when the cover is placed, there is immediate mechanical engagement and close contact, achieving reliable sealability even with a reduced cover size that minimizes dead space.
2Reliability
If the edge of the case is pressed to ensure close contact with the cover, then sealability is improved, but manufacturing complexity increases
Solution Approach 1:
The pressing operation that creates the protruding edge surface is replaced by laser welding technology. Instead of relying on mechanical deformation and complex pressing mechanisms, the edge of the case is directly welded to the cover, simplifying the coupling structure while ensuring reliable sealability through the weld bond.
3Manufacturing precision
If laser welding is used to couple the case and cover, then manufacturing precision is improved, but manufacturing cost increases
Solution Approach 1:
The laser welding parameters (power, speed, focal position) are optimized to match the specific material properties and geometric features of the case edge and cover. By adjusting these parameters, high-precision coupling is achieved while controlling energy consumption and processing time, thereby managing manufacturing costs effectively.
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
Enhances sealability, minimizes dead space, and increases battery capacity by optimizing the coupling structure between the case and cover.
Implementation Method 1
The cover may be laser-welded to the case in the state in which the edge of the case is in close contact with the cover.
Data Source
AI summary
Embodiments relates a secondary battery. The secondary battery includes an electrode assembly, a case configured to accommodate the electrode assembly and having one open surface, a plate-shaped cover coupled to the open surface of the case, a first terminal provided on a second surface of the case, other than the open surface, and electrically connected to the electrode assembly, a second terminal provided to be spaced apart from the first terminal and electrically connected to the electrode assembly, and an insulating member configured to insulate the first terminal from the case. The cover is coupled to the case in a state of being inserted into the case. According to embodiments, a coupling structure between a case and a cover of a small secondary battery improves sealability after liquid injection. The coupling structure minimizes a dead space. As the dead space is reduced, the capacity of the secondary battery may increase.