Solid Electrolyte Sheet Binder for Bend Resistance and Ion Conductivity
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Solution Overview
Problem
All-solid state secondary batteries face challenges in achieving high bend resistance, scratch resistance, and ion conductivity, particularly in the production of electrode and solid electrolyte layers, which are crucial for maintaining battery integrity and preventing short-circuits during manufacturing and use.
Innovation Solution
A solid electrolyte composition containing an inorganic solid electrolyte with a polymer binder having urethane bonds in its main chain and a graft structure is used, enhancing the mechanical properties and ion conductivity of the solid electrolyte layer, allowing for improved adhesion and reduced interface resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a graft polymer binder is used to improve adhesiveness between binder and inorganic solid electrolyte, then bonding property is improved, but bend resistance becomes insufficient
Solution Approach 1:
The patent uses a composite binder system combining polyurethane polymer (providing bend resistance through elastic recovery) with graft polymer (providing adhesiveness through functional groups). This composite approach allows simultaneous achievement of both bend resistance and adhesiveness that single polymers cannot provide alone.
Solution Approach 2:
The patent modifies the binder properties by selecting specific polyurethane polymers with appropriate glass transition temperatures and molecular weights, and controlling the degree of grafting on the graft polymer. These parameter adjustments optimize the balance between mechanical flexibility and adhesive strength.
2Productivity
If roll-to-roll method is used to improve productivity, then manufacturing efficiency is improved, but sheet characteristics (bend resistance and scratch resistance) become difficult to maintain
Solution Approach 1:
The patent incorporates bend-resistant polyurethane binder in advance during binder formulation, so that the solid electrolyte layer inherently possesses sufficient mechanical strength to withstand the mechanical stresses of roll-to-roll manufacturing processes, preventing defects before they occur.
Solution Approach 2:
The patent uses polyurethane polymer with appropriate glass transition temperature to create a flexible yet resilient binder matrix that can accommodate the bending and stretching operations in roll-to-roll manufacturing while maintaining sheet integrity and preventing cracks or scratches.
3Reliability
If inorganic solid electrolyte is used to eliminate organic electrolytic solution, then safety and energy density are improved, but mechanical toughness and defect resistance become challenges
Solution Approach 1:
The patent creates a homogeneous composite binder system where polyurethane and graft polymer are uniformly distributed and coordinated, ensuring consistent mechanical properties throughout the solid electrolyte layer. This homogeneity prevents weak points that could lead to cracks or defects while maintaining the safety benefits of inorganic solid electrolyte.
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 solid electrolyte-containing sheet with high bend resistance, scratch resistance, and ion conductivity, improving the productivity of all-solid state secondary batteries and preventing short-circuits, enabling their efficient industrial manufacturing.
Implementation Method 1
a method in which the adhesiveness (bonding property) between a binder and an inorganic solid electrolyte or the like is improved by using a solid electrolyte composition containing an inorganic solid electrolyte or the like and a binder
Implementation Method 2
an inorganic solid electrolyte is used, and thus an organic electrolytic solution becomes unnecessary. As a result, an all-solid state secondary battery can be manufactured by sequentially laminating an electrode layer that forms the negative electrode or the positive electrode and a solid electrolyte layer that forms the inorganic solid electrolyte
Data Source
Figure 1~2
Figure 3
AI summary
Provided are a solid electrolyte composition containing an inorganic solid electrolyte (A) having a conductivity of an ion of a metal belonging to Group I or II of the periodic table and a binder (B), in which the binder (B) is a polymer having at least one bond of a urethane bond, a urea bond, an amide bond, an imide bond, or an ester bond in a main chain and having a graft structure, a solid electrolyte-containing sheet and a manufacturing method therefor, an all-solid state secondary battery and a manufacturing method therefor, and a polymer having a specific hard segment and a graft structure and a non-aqueous solvent dispersion thereof