Battery Cell Case Hemming Around Cut Edges for Corrosion Control
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Solution Overview
Problem
Existing battery cases are prone to corrosion due to exposed cut surfaces, which can compromise safety, handling, sealing, and the overall life of the battery cell.
Innovation Solution
A battery cell design featuring a recessed portion, bent and hemming portions, and a cap assembly with a gasket to prevent corrosion, enhance safety, and improve sealing, using nickel-plated steel sheets to form a case that includes a recessed portion to support the cap assembly and a hemming process to seal the cut surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the case is cut to have a predetermined height to make the open end smooth, then the shape regularity is improved, but the cut surface is exposed and corrosion resistance deteriorates
Solution Approach 1:
The hemming operation is performed in advance before the case is cut to predetermined height. By pre-forming the hemmed portion that covers the cut surface, the invention ensures corrosion protection is established before the harmful exposure occurs during subsequent cutting operations.
Solution Approach 2:
The case forming process is divided into distinct sequential operations: first forming the hemmed portion, then cutting to height, and finally performing beading. This segmentation allows each operation to be optimized independently, with the hemming operation specifically addressing corrosion protection of the cut surface.
2Device complexity
If only deep drawing operation is performed without cutting, then manufacturing steps are reduced, but the open end has irregular shape and handling safety deteriorates
Solution Approach 1:
The hemming operation is performed before cutting to create a protective edge. This preliminary action ensures that when the case is later cut to the predetermined height for regular shaping, the cut surface is already protected, maintaining both manufacturing efficiency and handling safety.
3Shape
If the case is cut to predetermined height before beading, then the open end becomes smooth and sealing is improved, but the exposed cut surface reduces corrosion resistance
Solution Approach 1:
The hemming operation is performed in advance before the cutting operation. This ensures that the protective hemmed structure is already in place to cover and protect the cut surface when the case is subsequently cut to the predetermined height for smooth shaping.
Data Source
AI summary
The present disclosure relates to a battery cell comprising: an electrode assembly including a first electrode, a second electrode, and a separator disposed between the first electrode and the second electrode; a case having a first opening at one end and forming a space in which the electrode assembly is accommodated through the first opening; and a cap assembly coupled with the case to form the space together with the case and closing the first opening.