Electrode Assembly End Protective Layers Against Separator Shrinkage
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Solution Overview
Problem
The existing ceramic coatings on battery separators are prone to delamination and chalking, leading to safety issues due to separator shrinkage and potential short circuits when the battery temperature rises.
Innovation Solution
An electrode assembly with end protective layers that include a separator coating portion directly bonded to the non-contact surfaces of the separator, enhancing its mechanical strength and thermal stability, and preventing inward shrinkage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a ceramic layer is coated on the separator to improve heat resistance, then thermal stability is improved, but the ceramic layer is prone to delamination and chalking during use
Solution Approach 1:
The patent applies composite materials by combining the ceramic layer with a polymer coating layer to form a composite coating structure. The polymer layer (such as polyethylene or polypropylene) serves as a binding matrix that holds the ceramic particles together and adheres them to the separator substrate, preventing delamination and chalking while maintaining the thermal stability provided by the ceramic component.
2Temperature
If the separator protrudes outwards to provide non-contact surfaces, then thermal stability is improved, but the separator is prone to inward shrinkage during use
Solution Approach 1:
The patent applies preliminary anti-action by providing end protective layers that preemptively counteract the inward shrinkage force. These protective layers are positioned at the ends of the separator before shrinkage occurs, creating a physical barrier and structural support that prevents the separator from shrinking inward, thereby maintaining the protruding configuration and thermal stability.
Solution Approach 2:
The patent applies parameter changes by modifying the mechanical properties of the separator through the addition of end protective layers. These layers change the structural parameters (such as rigidity and dimensional stability) of the separator, enabling it to maintain its protruding shape and resist thermal shrinkage during battery operation.
3Temperature
If end protective layers are added to prevent separator shrinkage, then thermal stability is improved, but device complexity increases
Solution Approach 1:
The patent applies merging by integrating the end protective layers with the separator to form a unified structure. The protective layers are bonded to the separator ends, creating a combined component that functions as a single unit. This merging approach reduces the number of separate parts and assembly steps, thereby minimizing the increase in device complexity while still providing the necessary thermal stability and shrinkage 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 improves the thermal stability and mechanical strength of the separator, reducing the risk of bending deformation and electrode plate misalignment, thereby enhancing the safety and energy density of the battery.
Implementation Method 1
the end protective layer includes a separator coating portion which covers at least part of the non-contact surface and is directly bonded to the non-contact surface to form an integral structure with the separator
Implementation Method 2
the separator coating portion can improve the mechanical strength and thermal stability of the portions of the separator protruding outwards, which is conducive to preventing or reducing the inward shrinkage of the separator
Data Source
AI summary
An electrode assembly includes an electrode assembly body including positive and negative electrode plate body portions, and a separator isolating the positive electrode plate body portion from the negative electrode plate body portion, and protruding outwards at two ends of the electrode assembly body in a first direction relative to the positive and negative electrode plate body portions. Two ends of the separator in the first direction have non-contact surfaces that are not in contact with the positive or negative electrode plate body portion. The electrode assembly further includes end protective layers arranged at the two ends of the electrode assembly body in the first direction and forming an integral structure with the electrode assembly body. The end protective layer includes a separator coating portion at least partially covering the non-contact surface and directly bonded to the non-contact surface to form an integral structure with the separator.