Battery Separator Dispersant Composition for High-Temperature Stability
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Solution Overview
Problem
Conventional separators for non-aqueous electrolyte batteries lack sufficient heat resistance and stability during high-temperature events, such as internal short circuits, which can lead to safety issues like fuming, ignition, or explosion due to poor dispersibility and adhesive strength of inorganic fillers in heat-resistant porous layers.
Innovation Solution
A dispersant composition for the separator comprising a polymer with specific repeating units, including an alkene-based monomer, vinyl acetate-based monomer, and unsaturated functional groups, which forms crosslinking bonds to enhance the adhesion and dispersibility of inorganic fillers, thereby improving the heat resistance and high-temperature stability of the separator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conventional porous substrate (polyethylene or polypropylene film) is used as a separator, then the separator can block pores through melting at elevated temperatures to prevent short circuit, but the separator lacks sufficient heat resistance and shrinks or melts at temperatures of 600°C or higher during internal short circuit
Solution Approach 1:
The patent applies composite materials by combining an organic porous substrate with inorganic heat-resistant porous layers on one or both surfaces. The inorganic layer comprises inorganic particles (such as alumina, silica, or boehmite) dispersed in a binder polymer, creating a composite structure that maintains the flexibility and ion conductivity of the organic substrate while adding high-temperature stability and preventing shrinkage at temperatures of 600°C or higher during internal short circuit events
2Temperature
If an inorganic material with a dispersing agent (ethylene-vinyl acetate polymer) is used to form a heat-resistant porous layer, then the heat resistance is improved, but the dispersibility and adhesive strength are insufficient when the dispersant maintains poor dispersibility
Solution Approach 1:
The patent applies parameter changes by optimizing the molecular weight, composition ratio, and chemical structure of the binder polymer (using polymers with carboxyl groups, hydroxyl groups, or both). By adjusting these parameters, the patent achieves both excellent dispersibility of inorganic particles and strong adhesive strength to the porous substrate, while maintaining heat resistance up to 600°C or higher
3Reliability
If a heat-resistant porous layer is formed on the porous substrate to prevent short circuit, then the thermal stability is improved, but the adhesive strength between the inorganic filler and the substrate is insufficient
Solution Approach 1:
The patent applies parameter changes by selecting binder polymers with specific functional groups (carboxyl groups with pKa 3-6 or hydroxyl groups) and optimizing their molecular weight and composition ratios. These parameter changes enhance the adhesive strength between the inorganic heat-resistant layer and the porous substrate through improved chemical bonding and interfacial adhesion, while maintaining thermal stability during internal short circuit
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 adheres and disperses inorganic fillers, enhancing the heat resistance and stability of the separator, ensuring safety in high-temperature environments and preventing accidents like fuming, ignition, or explosion.
Implementation Method 1
a heat-resistant porous layer which comprises the dispersant composition and an inorganic filler
Implementation Method 2
a polymer containing a first repeating unit... a second repeating unit... and a third repeating unit... at least part of R32 may form a crosslinking bond with other repeating units in the copolymer
Data Source
AI summary
The present disclosure relates to a dispersant composition for a separator of a non-aqueous electrolyte battery, a separator of a non-aqueous electrolyte battery, and a non-aqueous electrolyte battery.