Bending Type Secondary Battery Can Curved Corners
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Solution Overview
Problem
Conventional battery can manufacturing methods, such as deep drawing and impact processes, are limited in reducing can thickness and result in thickness deviations and high manufacturing costs, with issues in achieving precise dimensional accuracy and preventing pinholes during welding.
Innovation Solution
A secondary battery with a bending type can that features curved portions at corners where three or four sides meet, reducing thickness deviations and improving safety by ensuring overlapping curvatures prevent pinholes during welding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional deep drawing or impact processes are used to manufacture battery cans, then manufacturing is feasible with existing processes, but can thickness cannot be sufficiently reduced and thickness deviation occurs across different areas
Solution Approach 1:
The patent changes the fundamental manufacturing parameter from conventional deep drawing or impact processes to a bending process. This parameter change enables simultaneous achievement of reduced can thickness (0.15mm or less) and uniform thickness distribution across different areas of the can, resolving the contradiction between thickness reduction and thickness uniformity.
Solution Approach 2:
The patent introduces curvature elements at the corners of the battery can where three or four sides meet. These curved portions are formed by bending the metal plate at specific angles (45° to 60°) before welding, which prevents pinhole formation during welding and improves both manufacturing precision and welding quality without increasing process complexity.
2Productivity
If conventional impact process is used to reduce processing steps and lower cost, then productivity improves, but thickness deviation and pinhole formation during welding occur
Solution Approach 1:
The patent applies preliminary bending actions to form curved portions at the corners of the metal plate before the welding process. By pre-forming these curved portions with specific angles (45° to 60°) and overlapping the bent sides, the patent eliminates pinhole formation during subsequent welding operations. This preliminary action maintains productivity while significantly improving manufacturing precision and welding quality.
3Weight of moving object
If can thickness is reduced to lower battery weight and cost, then weight and manufacturing cost decrease, but dimensional accuracy and thickness uniformity deteriorate
Solution Approach 1:
The patent changes the manufacturing process parameter to bending, which enables precise control of thin metal plates (0.15mm or less). This parameter change allows the can thickness to be reduced for weight reduction while simultaneously maintaining uniform thickness distribution and high dimensional accuracy through the controlled bending process and corner curvature formation.
Data Source
AI summary
A secondary battery includes an electrode assembly, a case accommodating the electrode assembly, and a cap assembly coupled to the case to seal the case, and the case includes a bottom portion, long side portions bent and extended from the bottom portion, a first short side portion bent and extended from the bottom portion, and second short side portions bent and extended from the long side portions, the first short side portion and the second short side portions connected to each other to define a short side portion, and curvatures located between the first short side portion and the second short side portions.