2-Cyanoethyl Binder for Heat-Resistant Battery Separator
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Solution Overview
Problem
Current lithium ion secondary batteries face challenges with heat resistance during internal short circuits, as conventional separators with polyolefin films melt or shrink, leading to potential fuming, ignition, and explosion, and existing heat-resistant porous layers with 2-cyanoethyl group-containing polymers require further enhancement for improved adhesion with inorganic filler particles.
Innovation Solution
A binder comprising a 2-cyanoethyl group-containing polymer with storage elasticity of 100 Pa or more, specifically in a mixed liquid of cyclic carbonate esters and chain carbonate esters with lithium phosphate hexafluoride, is used to create a heat-resistant porous layer with enhanced mechanical strength and adhesion in non-aqueous electrolyte batteries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional porous substrate such as polyolefin film is used as a separator, then the separator can block pores at moderate temperatures to prevent short circuit, but the separator shrinks or melts at high temperatures (600°C or higher) causing battery failure
Solution Approach 1:
The patent applies composite materials by combining a porous substrate with a heat-resistant porous layer containing inorganic filler particles and a specific binder. This composite structure allows the separator to maintain pore-blocking function at moderate temperatures while the inorganic filler provides heat resistance at high temperatures, preventing shrinkage and melting that would otherwise occur with conventional polyolefin films alone.
Solution Approach 2:
The patent utilizes porous materials by forming a heat-resistant porous layer with controlled porosity on the porous substrate. This porous structure allows ion transport while the inorganic filler particles provide thermal stability. The porous nature enables the layer to maintain its function as a separator while resisting heat-induced deformation up to 600°C and higher.
2Reliability
If a heat-resistant porous layer with 2-cyanoethyl group-containing polymer is used, then heat resistance is improved, but adhesion with inorganic filler particles requires further enhancement
Solution Approach 1:
The patent applies parameter changes by specifying that the 2-cyanoethyl group-containing polymer must have a storage elasticity of 100 Pa or more in the electrolyte solution. This parameter specification ensures the binder has sufficient elasticity to maintain strong adhesion with inorganic filler particles while providing heat resistance. The elasticity parameter directly influences the binder's ability to hold filler particles together and adhere to the substrate under thermal stress.
3Reliability
If the separator structure is enhanced with multiple layers and inorganic fillers, then heat resistance is improved, but the complexity of the separator structure increases
Solution Approach 1:
The patent applies segmentation by dividing the separator into distinct functional layers: a porous substrate layer for base separation and pore blocking, and a heat-resistant porous layer containing inorganic filler particles for thermal stability. This segmented structure allows each layer to perform its specific function optimally while maintaining overall simplicity. The clear functional division reduces complexity compared to fully integrated homogeneous structures.
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 provides a non-aqueous electrolyte battery with improved heat resistance and mechanical strength, preventing battery degradation and ensuring safe operation by maintaining the integrity of the separator during high-temperature events.
Implementation Method 1
the binder comprising at least a 2-cyanoethyl group-containing polymer having storage elasticity of 100 Pa or more in a mixed liquid of cyclic carbonate ester selected from the group consisting of ethylene carbonate, propylene carbonate and any combination thereof; a chain carbonate ester selected from the group consisting of ethyl methyl carbonate, dimethyl carbonate, diethyl carbonate and any combination thereof; and lithium phosphate hexafluoride
Implementation Method 2
When the temperature increases owing to the heat generated by short circuit, the separator comprising the porous substrate melts to block the pores
Implementation Method 3
a multilayer separator comprising a heat-resistant porous layer on one or both surfaces (i.e., front and back surfaces) of a porous substrate having fine pores
Data Source
AI summary
Provided is a binder used for a heat-resistant porous layer which is comprised by a separator; a separator which comprises the binder and which is comprised by a non-aqueous electrolyte battery with improved stability; and a non-aqueous electrolyte battery comprising the separator. More specifically, provided is a binder for a separator of a non-aqueous electrolyte battery, the binder comprising at least a 2-cyanoethyl group-containing polymer having storage elasticity of 100 Pa or more in a mixed liquid of specified cyclic carbonate ester, specified chain carbonate ester and lithium phosphate hexafluoride.