Polymer electrolyte, electrode active material binder, and secondary battery
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Solution Overview
Problem
Lithium ion secondary batteries face challenges with polymer electrolytes that soften at high temperatures, leading to decreased strength and increased risk of short circuits, and existing solid electrolytes have difficulty enlarging the interface with active materials, affecting ion conductivity.
Innovation Solution
A polymer electrolyte with a three-dimensional cross-linked polyurethane structure and cationic structure is introduced, enhancing mechanical strength and ion conductivity, and an electrode active material binder is developed to improve interface contact with active materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a polyurethane is used in a polymer electrolyte, then it is easy to enlarge the interface with active material and mechanical properties are excellent, but the polyurethane easily softens at high temperatures and strength decreases
Solution Approach 1:
The patent applies parameter changes by modifying the molecular structure of polyurethane through introducing a three-dimensional cross-linked structure. This structural modification changes the thermal and mechanical parameters of the material, enabling it to maintain strength at high temperatures while preserving interface enlargement capability with active materials.
Solution Approach 2:
The patent creates a composite material system by combining polyurethane with a three-dimensional cross-linked structure. This composite approach integrates the advantages of polyurethane (easy interface enlargement, good mechanical properties) with the heat resistance benefits of the cross-linked network, resolving the contradiction between mechanical strength and high temperature stability.
2Strength
If a three-dimensional cross-linked structure is introduced into polyurethane to suppress strength decrease under high temperature, then strength is maintained, but ion conductivity decreases in some cases
Solution Approach 1:
The patent carefully controls the cross-linking degree as a critical parameter to balance strength and ion conductivity. By optimizing the cross-linking density rather than simply increasing it, the patent achieves sufficient high-temperature strength while maintaining adequate ion conductivity for battery operation.
Solution Approach 2:
The three-dimensional cross-linked structure is introduced in a controlled manner to create local structural enhancements rather than uniform dense cross-linking throughout. This localized approach provides strength where needed while preserving ion transport pathways in other regions, resolving the contradiction between strength and ion conductivity.
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 polymer electrolyte maintains strength and ion conductivity under high temperatures, improving battery performance by reducing the risk of short circuits and enhancing charge/discharge characteristics.
Implementation Method 1
the polymer electrolyte has high ion conductivity
Data Source
AI summary
A polymer electrolyte comprising a polyurethane, a lithium salt, and an anion, wherein the polyurethane has a three-dimensional cross-linked structure and has a cationic structure in a molecule.