Battery Separator Using Barium Sulfate for Heat Resistance
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Solution Overview
Problem
Current separators for non-aqueous secondary batteries, such as those containing magnesium hydroxide or alumina, are prone to gas generation and lack sufficient heat resistance, which can compromise battery safety.
Innovation Solution
A separator with a porous substrate and a heat-resistant porous layer containing barium sulfate particles, where the average primary particle size of barium sulfate is between 0.01 µm and 0.30 µm, and a polyvinylidene fluoride type resin with a weight average molecular weight of 600,000 to 3,000,000 is used, providing enhanced heat resistance and reduced gas generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a separator includes a porous layer containing magnesium hydroxide or alumina on a porous substrate, then heat resistance is improved, but gas generation occurs due to decomposition of electrolyte
Solution Approach 1:
The patent changes the material composition parameter from conventional magnesium hydroxide or alumina to barium sulfate particles with specifically controlled primary particle size (0.01 µm to less than 0.30 µm). This parameter change resolves the contradiction by selecting a material that provides heat resistance without causing electrolyte decomposition and gas generation.
Solution Approach 2:
The patent creates a composite porous layer combining barium sulfate particles with a binder resin (such as polyvinylidene fluoride type resin). This composite material approach allows the separator to maintain mechanical integrity and heat resistance while avoiding the harmful gas generation associated with conventional materials.
2Ease of manufacture
If the porous layer contains barium sulfate particles with larger primary particle size, then manufacturing is easier, but heat resistivity is reduced
Solution Approach 1:
The patent optimizes the primary particle size parameter of barium sulfate particles to a specific range (0.01 µm to less than 0.30 µm). This parameter optimization achieves heat resistivity improvement while maintaining manufacturability, as the particles are small enough to provide effective heat resistance but large enough to be handled and processed reasonably.
Data Source
AI summary
Provided is a separator for a non-aqueous secondary battery containing a porous substrate; and a heat resistant porous layer that is provided on one side or on both sides of the porous substrate, and that contains a binder resin and barium sulfate particles, in which an average primary particle size of the barium sulfate particles contained in the heat resistant porous layer is from 0.01 µm to less than 0.30 µm.