Insulated Electrode Plate Welding Layout for Short-Circuit Prevention
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Solution Overview
Problem
Current secondary battery current collectors face safety issues due to short circuits caused by welded-through metal during welding and increased internal resistance from metal slag falling into the battery, which are not effectively addressed by traditional tab forming structures.
Innovation Solution
An electrode plate design featuring a current collector with a first insulation layer covering the transfer welding region, preventing slag and particulates from entering the active material layer and reducing internal resistance, while also improving ion permeability through the use of insulating materials like polyethylene or polyvinylidene chloride films.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional tab forming structure is used for welding electrical connection member to current collector, then welding connection can be established, but short circuit occurs due to welded-through metal and metal slag falling into battery
Solution Approach 1:
An insulation layer is introduced as an intermediary component between the welding area and the active material layer. This insulation layer prevents direct contact between welded-through metal and the active material, thereby eliminating the short circuit hazard while maintaining the electrical connection functionality.
Solution Approach 2:
The current collector is divided into functionally distinct regions: a welding area for electrical connection and an active material arrangement area for electrochemical function. The insulation layer is selectively positioned to cover only the welding area, segmenting the harmful welding byproducts from the active material while preserving electrical conductivity where needed.
2Reliability
If welding is performed to connect electrical connection member to current collector, then electrical connection is achieved, but internal resistance increases due to metal slag contamination
Solution Approach 1:
The insulation layer serves as a protective intermediary that captures and contains metal slag generated during welding. By positioning the insulation layer over the welding area, it prevents slag from falling into the battery interior, thereby maintaining low internal resistance and preventing performance degradation.
3Reliability
If insulation layer is added to prevent short circuit, then safety is improved, but device complexity increases
Solution Approach 1:
The insulation layer is applied locally only to the welding area of the current collector rather than covering the entire structure. This localized application provides the necessary short circuit prevention exactly where welding occurs, while leaving other areas of the current collector simple and unmodified, thus minimizing the increase in device complexity.
Data Source
AI summary
An electrode plate, an electrode assembly, and a secondary battery are provided. The electrode plate includes a current collector, an active material layer arranged on one surface of the current collector, and an electrical connection member electrically connected to the current collector. The active material layer is arranged on a main body portion of the current collector, the electrical connection member and the current collector are connected to each other by welding at an edge of the current collector, the welding connection region is referred to as a transfer welding region, and the current collector includes a support layer and an electrically conductive layer arranged on one surface of the support layer. The electrode plate further includes a first insulation layer arranged on a further surface of the current collector and covering at least the entirety of the transfer welding region when viewed in a thickness direction of the electrode plate.