Secondary Battery Electrode Insulation Layout for Short Prevention
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Solution Overview
Problem
Lithium secondary batteries face issues of shorts and fractures due to direct contact between uncoated portions of the cathode and anode, which can lead to safety hazards and manufacturing defects.
Innovation Solution
The electrode design includes insulating layers on both surfaces of coated and uncoated portions with mismatched end positions to prevent direct contact and distribute stress, using materials like fluorine resin and polyimide-based resins to form consecutive layers with varying lengths and thicknesses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If insulating layers are formed on both surfaces of the electrode, then short prevention between anode and cathode is improved, but device complexity increases
Solution Approach 1:
The insulating layer is segmented into two distinct parts: a first insulating layer formed on the active material layer and a second insulating layer formed on the uncoated portion. This segmentation allows each layer to serve specific functions - the first layer provides insulation where active material is present, while the second layer insulates the conductive uncoated portion, thereby preventing shorts without requiring a single complex insulating structure to cover all scenarios.
Solution Approach 2:
Different insulating properties are applied to different regions of the electrode. The uncoated portion, which is highly conductive and poses a shorting risk, receives a dedicated second insulating layer. The active material layer region receives a first insulating layer. This local differentiation of insulating quality ensures that insulation is provided precisely where needed, improving reliability without uniformly increasing complexity across the entire electrode structure.
2Reliability
If insulating layers are formed on uncoated portions, then safety is improved by preventing shorts, but manufacturing complexity increases
Solution Approach 1:
The insulating layers are formed on the electrode surfaces before the electrode assembly is stacked with other components. By performing the insulation operation in advance, during the electrode manufacturing process rather than during assembly, the patent avoids adding complex steps to the battery assembly process. The insulating layers are integrated into the electrode fabrication workflow, making the safety enhancement part of the base manufacturing process.
Solution Approach 2:
The formation of insulating layers is merged with the existing electrode manufacturing process. Instead of treating insulation as a separate post-processing step or assembly-time intervention, the patent combines the insulating layer formation with the electrode fabrication steps (coating, drying, rolling), thereby improving safety without significantly increasing overall manufacturing complexity.
3Strength
If the ends of insulating layers are positioned differently on both surfaces, then stress distribution is improved reducing fractures, but manufacturing precision requirements increase
Solution Approach 1:
The patent intentionally introduces asymmetry in the positioning of insulating layer ends on opposite surfaces of the electrode. The first insulating layer on one surface extends to a different position than the corresponding layer on the other surface. This asymmetric configuration creates a staggered stress distribution pattern during rolling and assembly, preventing stress concentration at aligned boundaries and reducing the risk of fractures at the interface between coated and uncoated portions.
Solution Approach 2:
The asymmetric positioning of insulating layer ends serves as a preventive measure against stress concentration and electrode fracture. By deliberately misaligning the ends of insulating layers on opposite surfaces, the patent creates a built-in stress-distributing feature that cushions against the high pressures applied during rolling and assembly, preventing fractures before they can occur at the vulnerable boundaries between coated and uncoated portions.
Data Source
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AI summary
The present disclosure relates to an electrode for a secondary battery and a secondary battery comprising the same, and the present disclosure provides an electrode for a secondary battery includes a first surface and a second surface, positioned opposite to the first surface, wherein the first surface includes a first active portion in which an electrode active material layer is formed on an electrode current collector and a first uncoated portion in which an electrode active material layer is not formed, wherein the second surface includes a second active portion in which an electrode active material layer is formed on an electrode current collector, and a second uncoated portion in which an electrode active material layer is not formed, independently of the first surface, wherein the first surface includes a first active portion insulating layer formed on the first active portion and a first uncoated portion insulating layer formed on the first uncoated portion, wherein the second surface includes a second active portion insulating layer formed on the second active portion and a second uncoated portion insulating layer formed on the second uncoated portion, and wherein a position of an end of the first active portion insulating layer and a position of an end of the second active portion insulating layer are different.