Wound Battery Cell Bent-Region Insulation Against Dendrite Shorts
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Solution Overview
Problem
Dendrites easily grow in the bent regions of existing battery cell electrode assemblies, leading to internal short circuits and affecting the safety and service life of the battery cell.
Innovation Solution
A battery cell design that includes a porous insulation layer disposed between the bent regions of the electrode assembly and the separator, which allows active ions to penetrate freely while hindering dendrite formation and reducing bending stress on the electrode plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the electrode assembly is wound into a compact structure, then the energy density is improved, but dendrites are easily grown in the bent region causing internal short circuits
Solution Approach 1:
A porous insulation layer is introduced as an intermediary component between the electrode plate and the separator in the bent region. This layer serves as a mediator that allows active ions to pass through while providing mechanical insulation to prevent dendrite-induced short circuits, thus resolving the contradiction between compact structure and safety.
Solution Approach 2:
The porous insulation layer is selectively applied only in the bent region where dendrite growth is most problematic, rather than throughout the entire electrode assembly. This localized approach maintains high energy density while providing targeted protection against short circuits in the critical area.
2Productivity
If the separator is placed close to the electrode plate, then the charging and discharging performance is improved, but the risk of short circuit due to dendrite growth increases
Solution Approach 1:
The porous insulation layer acts as an additional intermediary between the electrode plate and the separator, creating a dual-layer barrier system. This allows the separator to remain close to the electrode plate for good ionic conductivity while the porous insulation layer provides an extra layer of protection against dendrite penetration.
Solution Approach 2:
The porous insulation layer is made from porous materials that allow active ions to pass through freely, maintaining good charging and discharging performance. Simultaneously, the porous structure provides mechanical strength to block dendrite growth and prevent short circuits.
3Reliability
If a dense insulation layer is used to prevent dendrite growth, then safety is improved, but active ion transport is hindered reducing charging performance
Solution Approach 1:
The insulation layer is designed with a porous structure that allows active ions to transport freely through the material. The porosity ensures that charging performance is not significantly hindered while the overall structure still provides effective barrier against dendrite growth.
Solution Approach 2:
The porous insulation layer is constructed from composite materials that combine the properties of ionic conductivity with mechanical barrier properties. This composite structure enables simultaneous achievement of good charging performance and effective dendrite prevention.
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 solution effectively delays the occurrence of internal short circuits, prolongs the service life of the battery cell, and enhances its safety by reducing metal precipitation and dendrite growth.
Implementation Method 1
the pores of the porous insulation layer can allow active ions to penetrate freely
Implementation Method 2
the porous insulation layer with insulation properties can also hinder the formation of dendrites
Implementation Method 3
the porous insulation layer disposed between the bent portion of the electrode plate and the separator can further buffer the bending stress borne by the bent part of the electrode plate
Data Source
AI summary
This application discloses a battery cell, a battery, and an electric apparatus. The battery cell includes at least one electrode assembly. The electrode assembly includes a positive electrode plate, a negative electrode plate, a separator, and a porous insulation layer. The positive electrode plate, the separator, and the negative electrode plate are stacked and wound. At least a portion of the porous insulation layer is disposed in a bent region of the electrode assembly, and the porous insulation layer is disposed between the positive electrode plate and the separator or disposed between the negative electrode plate and the separator. Based on the above structure, the service life of the battery cell can correspondingly be prolonged, and the safety of the battery cell can correspondingly be improved.