Laminated Battery Separator Surface Uniformity for Heat and Rate Performance
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Solution Overview
Problem
Conventional laminated separators for nonaqueous electrolyte secondary batteries face challenges in achieving excellent rate characteristics and heat resistance.
Innovation Solution
A laminated separator comprising a polyolefin-based substrate with a heat-resistant layer on one or both surfaces, and a particle layer on at least one side, where the standard deviation of the 60-degree specular gloss on the surface with the particle layer is not more than 0.80.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional laminated separator structure is used, then the basic separator function is provided, but the rate characteristic and heat resistance are insufficient
Solution Approach 1:
The patent applies composite materials by combining a polyolefin-based substrate with a heat-resistant layer containing aromatic resin and inorganic particles. This composite structure provides both the shutdown function of polyolefin at low temperatures and the heat resistance of aromatic resin at high temperatures, while the inorganic particles enhance structural stability to maintain rate characteristics.
Solution Approach 2:
The patent changes physical parameters by controlling the gloss standard deviation to not more than 0.80, which indicates uniform particle distribution in the heat-resistant layer. This parameter control ensures consistent thermal and mechanical properties throughout the separator, improving both heat resistance and rate characteristics through uniform performance.
2Reliability
If the particle layer is provided on the separator surface, then heat resistance is improved, but uneven deformation may occur
Solution Approach 1:
The patent applies local quality by providing the heat-resistant layer with inorganic particles on specific surfaces of the polyolefin substrate. The controlled gloss standard deviation ensures that particles are uniformly distributed in the heat-resistant layer, creating consistent local properties that prevent uneven deformation while maintaining heat resistance.
3Reliability
If the gloss standard deviation is reduced to not more than 0.80, then uniform bonding with electrodes is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The patent changes the manufacturing parameter by specifying a gloss standard deviation of not more than 0.80, which serves as a quantitative control criterion for particle distribution uniformity. This parameter change translates the qualitative requirement of uniform bonding into a measurable and controllable manufacturing specification.
Data Source
AI summary
A laminated separator for a nonaqueous electrolyte secondary battery is provided which makes it possible to obtain a battery having an excellent rate characteristic and which has excellent heat resistance. A laminated separator for a nonaqueous electrolyte secondary battery according to the present disclosure includes a polyolefin-based substrate and a heat-resistant layer that is provided on one surface or both surfaces of the polyolefin-based substrate, the laminated separator including a particle layer which is provided on at least one side of the laminated separator, a standard deviation of a 60-degree specular gloss on a surface which is located on the at least one side on which the particle layer is provided being not more than 0.80.