Battery Cell Case Hemming Structure for Corrosion-Resistant Sealing
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Solution Overview
Problem
Existing battery cases are prone to corrosion at cut surfaces due to exposure, which affects safety, handling, sealing, and the overall life of the battery cell.
Innovation Solution
A battery cell design featuring a recessed portion, bent portion, and hemming portion in the case structure, combined with a cap assembly, to prevent corrosion and enhance sealing, using nickel-plated steel sheets and a gasket for secure closure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the case is cut to have a predetermined height, then the open end becomes a smooth shape, but the cut surface is exposed and not nickel-plated, leading to corrosion
Solution Approach 1:
The patent applies a protective film or coating on the cut surface of the case to prevent corrosion. The nickel-plated steel sheet case is covered with an additional protective layer that seals the exposed cut surface, creating a barrier against environmental factors while maintaining the smooth shape achieved by cutting.
2Productivity
If only deep drawing operation is performed, then the case is formed efficiently, but the open end has an irregular shape requiring additional cutting
Solution Approach 1:
The patent performs the cutting operation to create a smooth open end shape before the deep drawing operation. By pre-cutting the nickel-plated steel sheet to the desired height and shape, the subsequent deep drawing process can proceed efficiently without requiring additional trimming or finishing operations on the open end.
3Ease of manufacture
If the case structure is simplified, then manufacturing is easier, but corrosion protection and sealing are compromised
Solution Approach 1:
The patent uses composite construction by combining nickel-plated steel sheet with additional protective coatings and sealing elements. The case structure integrates multiple materials - the base nickel-plated steel provides structural strength, while additional protective layers and sealants provide corrosion resistance and sealing, achieving enhanced protection without significantly complicating the manufacturing process.
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
The design effectively prevents corrosion, ensures safe handling, improves the fixation of the case and cap assembly, and enhances the sealing integrity, thereby extending the battery's lifespan.
Implementation Method 1
since the cut surface exposed by cutting the case is not nickel-plated, the steel sheet may be exposed to air as it. As a result, corrosion of the case can proceed through the exposed cut surface
Implementation Method 2
Generally, cases are made using nickel-plated steel sheets to prevent corrosion
Data Source
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Figure 3A
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.