Battery Cell Welding Region Insulation Against Separator Piercing
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Solution Overview
Problem
Battery cells face safety issues due to short circuits caused by burrs and shavings in the welding region piercing the separator, leading to potential fires or explosions.
Innovation Solution
A protective layer is disposed on the welding region to cover burrs and shavings, using insulation materials like acrylic acid, hot-melt adhesive, or polypropylene to prevent short circuits and insulate electrode plates, while maintaining a specific size and thickness to minimize space occupation and maintain energy density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective layer is added to cover the welding region, then safety performance is improved by preventing short circuits, but device complexity increases due to additional structural components
Solution Approach 1:
The protective layer is integrated with the insulating layer of the current collector, combining multiple functions (protection against burrs, electrical insulation, and structural support) into a single unified component, thereby reducing overall device complexity while maintaining safety improvements
Solution Approach 2:
The protective layer serves as an intermediary element between the welding region and the separator, mediating the potential harmful interaction by providing a protective barrier that prevents burrs from piercing the separator while maintaining electrical insulation properties
2Reliability
If the protective layer is made thicker to better cover burrs and shavings, then safety performance is improved, but volume of the battery cell increases reducing energy density
Solution Approach 1:
The thickness of the protective layer is optimized within a specific range (5-50 micrometers) to achieve the necessary protection against burrs and shavings while minimizing volume occupation. This parameter optimization allows the protective layer to be thin enough to maintain energy density but thick enough to provide effective safety coverage
Solution Approach 2:
The protective layer is applied specifically to the welding region where burrs and shavings are most likely to occur, rather than uniformly across the entire current collector. This localized application provides targeted protection where needed while minimizing overall volume consumption and preserving energy density
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 protective layer effectively reduces the risk of short circuits, enhancing safety performance by covering potential piercing points without significantly decreasing the battery's energy density.
Implementation Method 1
the protective layer can cover burrs, shavings, and the like in the welding region to reduce the risk of short circuit inside the battery cell caused by the burrs, shavings, and the like in the welding region piercing a separator of the electrode assembly
Implementation Method 2
The first current collector includes a first conductive layer, an insulation layer, and a second conductive layer
Implementation Method 3
The conductive member is disposed on both the first conductive layer and the second conductive layer, and is welded to the first region to form a welding region for mutual conductive connection
Data Source
AI summary
A battery cell includes a housing, an electrode assembly, a conductive member, and a protective layer. The electrode assembly is accommodated in the housing. The electrode assembly includes a first electrode plate and a second electrode plate with opposite polarities. The first electrode plate includes a first current collector and a first active substance layer. The first current collector includes a main body portion and a first region located in a width direction of the first electrode plate, the first active substance layer being provided on a surface of the main body portion and the first active substance layer being not provided on a surface of the first region. The conductive member is welded to the first region to form a welding region. The protective layer is disposed on a surface of the welding region.