Wound Electrode Assembly With Multi-Layer Isolation in Bent Areas
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Solution Overview
Problem
Battery cells face safety risks due to metal ion precipitation and short circuits, particularly in bent areas where stress concentration leads to active substance peeling-off and dendrite formation.
Innovation Solution
Incorporating a multi-layer structural area within the isolation assembly in the electrode assembly, specifically in the bent areas, to block dendrites and prevent conduction between the electrode plates, thereby reducing the risk of short circuits and improving safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single-layer isolation assembly is used in the bent area, then the device complexity is reduced, but the reliability decreases due to dendrite penetration and short circuit risks
Solution Approach 1:
The isolation assembly employs a multi-layer composite structure comprising a first isolation layer, a second isolation layer, and a third isolation layer. Each layer serves specific functions: the first layer provides initial isolation, the second layer blocks dendrites that penetrate the first layer, and the third layer provides redundant protection. This composite structure significantly enhances short circuit prevention capability while managing the complexity through functional differentiation of each layer.
Solution Approach 2:
The multi-layer isolation assembly is pre-configured in the bent area before battery operation to provide beforehand protection against dendrite formation and short circuits. The redundant layers are positioned in advance to cushion against the harmful effects of metal ion precipitation and dendrite penetration, ensuring reliability even when dendrites form during battery cycling.
2Reliability
If the isolation assembly covers the entire electrode plate surface, then the reliability improves by blocking all potential dendrite paths, but the loss of substance increases due to excessive isolation material
Solution Approach 1:
The multi-layer isolation assembly is selectively positioned only in the bent area where dendrite formation and metal ion precipitation are most likely to occur. This localized approach provides targeted dendrite blocking capability precisely where it is needed most, while avoiding the waste of isolation material in areas where it is not required, thus optimizing both reliability and material efficiency.
3Shape
If the curvature of bent portions is increased, then the electrode plate can accommodate better, but the stress concentration worsens leading to active substance peeling-off
Solution Approach 1:
The multi-layer isolation assembly is pre-positioned in the bent area to provide beforehand protection against the consequences of stress concentration. While the bent area geometry causes stress concentration and active substance peeling-off, the isolation layers are already in place to prevent dendrite formation from the precipitated metal ions, cushioning against the harmful effects of the stress-induced peeling.
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 multi-layer structural area effectively reduces the probability of short circuits and improves the service life and safety of the electrode assembly by blocking dendrites and managing metal ion precipitation.
Implementation Method 1
the multi-layer structural area can block the dendrites of the precipitated metal layer, so as to reduce the probability of conduction between the first electrode plate and the second electrode plate
Implementation Method 2
the isolation assembly is configured to isolate the first electrode plate from the second electrode plate
Data Source
AI summary
The embodiments of the present application provide an electrode assembly, a battery cell, a battery, and an electrical device. The electrode assembly includes a first electrode plate, a second electrode plate, and an isolation assembly. The first electrode plate and the second electrode plate have opposite polarities, and the isolation assembly is configured to isolate the first electrode plate from the second electrode plate. The first electrode plate, the second electrode plate, and the isolation assembly are wound and form a bent area. The isolation assembly includes a multi-layer structural area provided between the first electrode plate and the second electrode plate, and at least a portion of the multi-layer structural area is provided in the bent area.