Block Copolymer Electrolyte for Secondary Battery Energy Density
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Solution Overview
Problem
Current secondary batteries with electrolyte layers containing polymer compounds do not achieve sufficient battery characteristics, such as energy density and discharge load characteristics, and are prone to acute heat generation during internal short circuits.
Innovation Solution
A secondary battery configuration that includes a cathode, an anode, and an electrolyte layer with a nonaqueous electrolytic solution and a polymer compound containing a block copolymer with vinylidene fluoride, hexafluoro propylene, and one or more of monomethyl maleate, trifluoroethylene, and chlorotrifluoroethylene as polymerization units, which enhances the battery's mechanical strength and ion conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a random copolymer containing vinylidene fluoride and hexafluoro propylene is used to improve lithium ion mobility, then ion conductivity is improved, but energy density and discharge load characteristics deteriorate
Solution Approach 1:
The patent uses a block copolymer composite structure combining vinylidene fluoride (VDF) segments for ion conductivity and hexafluoro propylene (HFP) segments for mechanical strength and energy density. This composite approach allows simultaneous optimization of lithium ion mobility and energy density by distributing different functional properties in distinct polymer blocks rather than mixing randomly
Solution Approach 2:
The block copolymer structure creates local regions with different properties: VDF-rich blocks provide high lithium ion mobility while HFP-rich blocks provide mechanical strength and higher energy density. This local differentiation allows each region to optimize its specific function without compromising the other
2Use of energy by moving object
If a block copolymer containing vinylidene fluoride and hexafluoro propylene is used to improve energy density, then energy density is improved, but discharge load characteristics deteriorate
Solution Approach 1:
The block copolymer creates a composite structure where HFP blocks contribute to energy density while VDF blocks maintain discharge load characteristics through their superior ion conductivity. The block architecture allows both properties to coexist without the trade-off seen in random copolymers
Solution Approach 2:
The patent optimizes the block length ratios and composition percentages of VDF and HFP segments to achieve the right balance between energy density and discharge load characteristics. By adjusting these parameters, the material can be tuned to meet specific performance requirements
3Object-affected harmful factors
If monomethyl maleate is added as a denaturing agent to prevent acute heat generation, then thermal safety is improved, but battery characteristics and performance deteriorate
Solution Approach 1:
The patent removes the denaturing agent (monomethyl maleate) from the system entirely and replaces it with an intrinsic block copolymer structure that provides both the desired thermal safety and maintained battery performance. The block copolymer's inherent structure prevents acute heat generation without the need for harmful additives
Solution Approach 2:
The block copolymer structure acts as an intermediary that provides thermal safety through its inherent molecular architecture rather than requiring external denaturing agents. The HFP blocks specifically provide thermal stability while maintaining electrochemical performance
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
This configuration improves the battery's energy density, cycle characteristics, and prevents acute heat generation, resulting in superior battery performance and stability.
Implementation Method 1
a block copolymer containing vinylidene fluoride, hexafluoro propylene, and one or more of monomethyl maleate, trifluoroethylene, and chlorotrifluoroethylene as polymerization units, which enhances the battery's mechanical strength and ion conductivity
Data Source
AI summary
A secondary battery includes: a cathode; an anode; and an electrolyte layer containing a nonaqueous electrolytic solution and a polymer compound, wherein the polymer compound contains a block copolymer, and the block copolymer contains vinylidene fluoride, hexafluoro propylene, and one or more of monomethyl maleate, trifluoroethylene, and chlorotrifluoroethylene as polymerization units.