Organic-Inorganic Composite Layer for Lithium Battery Safety
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Solution Overview
Problem
Traditional lithium batteries face safety issues due to internal short circuits, which cause heat accumulation, leading to separator deformation and potential explosions, and existing thermal barrier materials increase internal resistance and are prone to particle aggregation, affecting processability and safety.
Innovation Solution
An organic-inorganic composite layer with a weight ratio of 10:90 to 95:5 of organic polymer to composite inorganic particles, featuring at least two structural configurations stacked in a staggered configuration, is introduced between the electrodes and separator, enhancing adhesion, dispersibility, and processability while reducing inorganic material ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thermal barrier material with high content of inorganic particles is used to strengthen the separator and prevent internal short circuit, then the safety of the battery is increased, but the internal resistance of the battery is readily increased
Solution Approach 1:
The patent uses a composite material system consisting of organic polymer binder and inorganic particles (such as alumina, silica, or boehmite) to create a thermal barrier layer. This composite structure allows the organic component to provide ion conductivity and flexibility while the inorganic component provides thermal stability and mechanical strength, thereby reducing internal resistance while maintaining safety.
2Strength
If a thermal barrier material with high content of inorganic particles is used to strengthen the separator, then the mechanical properties of the separator are improved, but the inorganic particles are readily peeled off when used in a charge/discharge process
Solution Approach 1:
The organic polymer binder (such as polyvinylidene fluoride, carboxymethyl cellulose, or starch) acts as an adhesive matrix that binds inorganic particles together and to the separator substrate. This composite structure prevents particle peeling during charge/discharge cycles while maintaining the mechanical reinforcement provided by the inorganic particles.
Solution Approach 2:
The organic polymer binder serves as an intermediary substance between the inorganic particles and the separator. It provides a bonding interface that ensures strong adhesion of inorganic particles to the separator, preventing particle detachment during battery operation while allowing the inorganic particles to maintain their structural reinforcement function.
3Reliability
If a thermal barrier material with high content of inorganic particles is used, then the protective function is enhanced, but the inorganic particles are readily aggregated and subsided, affecting processability
Solution Approach 1:
The organic polymer binder creates a continuous matrix that disperses and stabilizes inorganic particles, preventing aggregation and sedimentation. This composite formulation improves the processability of the thermal barrier material during coating and drying processes while maintaining the protective function provided by the inorganic particles.
Data Source
AI summary
An organic-inorganic composite layer for a lithium battery includes an organic polymer and a plurality of composite inorganic particles. The weight ratio of the organic polymer to the composite inorganic particles is 10:90 to 95:5, wherein the composite inorganic particles have at least two structural configurations stacked in staggered configuration.