Composite Battery Separator Coating for Dendrite Short-Circuit Prevention
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Solution Overview
Problem
Secondary batteries face reliability issues due to the formation of metallic dendrites that can pierce through the separator, leading to short circuits between the positive and negative electrode plates, which compromises safety and performance.
Innovation Solution
A separator comprising a coating layer with first particles (molybdenum disulfide, silicon oxide, or conductive carbon particles) between two porous base films, which undergo redox reactions with metallic dendrites to prevent them from piercing through, enhancing the separator's reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional separator is used, then the battery structure is simple and manufacturing is easy, but metallic dendrites can pierce through the separator causing short circuits and reducing reliability
Solution Approach 1:
The separator is constructed as a composite structure with a base film and a coating layer containing first particles (molybdenum disulfide, silicon oxide, or conductive carbon particles). This composite design allows the separator to maintain its mechanical integrity while the coating layer provides redox reaction capability to neutralize metallic dendrites, thereby resolving the contradiction between reliability improvement and structural complexity.
Solution Approach 2:
The coating layer acts as an intermediary between the electrode plates and the metallic dendrites. It provides a chemical barrier that reacts with dendrites through redox reactions, preventing direct contact and short circuits. This intermediary layer enhances reliability without requiring fundamental changes to the overall separator structure.
2Reliability
If the separator thickness is increased to prevent dendrite piercing, then reliability improves, but the energy density of the battery decreases
Solution Approach 1:
By using a composite structure with a thin base film and a functional coating layer, the separator achieves high reliability without increasing overall thickness. The coating layer provides dendrite-neutralizing functionality at a molecular level, allowing the base film to remain thin and thus maintaining high energy density while preventing short circuits.
Solution Approach 2:
The invention changes the chemical parameters of the separator by incorporating particles with specific redox properties (molybdenum disulfide, silicon oxide, or conductive carbon particles). This parameter change enables the separator to actively neutralize dendrites chemically rather than relying solely on physical thickness, thereby maintaining thin structure and high energy density.
3Reliability
If a coating layer with first particles is added to the separator, then the ability to neutralize metallic dendrites improves, but the manufacturing complexity increases
Solution Approach 1:
The coating layer is designed with porous characteristics that allow it to be formed by simple coating processes. The porous structure enables the first particles to be evenly distributed and maintains ion permeability while providing sufficient surface area for redox reactions with metallic dendrites, balancing manufacturing simplicity with enhanced dendrite neutralization capability.
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 coating layer effectively isolates the electrode plates, reducing the risk of short circuits and enhancing the energy density and reliability of the secondary battery by preventing the risk of short circuits, thereby improving the battery's safety and performance.
Implementation Method 1
the coating layer in the separator can undergo a redox reaction with the metallic dendrites
Data Source
AI summary
Embodiments of the present application provide an isolation film, a preparation method therefor, and a secondary battery and an electric apparatus related thereto. The isolation film comprises a first porous base film, a second porous base film, and a coating layer. The coating layer is arranged between the first porous base film and the second porous base film. The coating layer comprises first particles. The first particles comprise at least one of molybdenum disulfide, silicon oxide, a transition metal oxide, or conductive carbon particles.