Nonflammable Gel-Polymer Electrolyte for Battery Swelling Control
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Solution Overview
Problem
Conventional battery electrolytes are prone to flammability and thermal runaway, leading to safety risks during overcharging and penetration, with liquid electrolytes experiencing significant thickness changes and temperature increases.
Innovation Solution
A polymer electrolyte system comprising a solvent mixture with high boiling point and nonflammable components, along with a diluent to reduce viscosity, is used to form a homogeneous gel-polymer electrolyte, enhancing safety by limiting thickness change and thermal runaway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional liquid electrolytes are used in batteries, then ionic conductivity and electrochemical performance are achieved, but flammability and thermal runaway risks increase significantly
Solution Approach 1:
The patent changes the physical and chemical parameters of the electrolyte by using high-boiling-point solvents (boiling point >150°C) such as phosphates, phosphonates, sulfones, and carbonates, replacing conventional flammable solvents. This parameter change eliminates flammability while maintaining ionic conductivity through careful selection of salt-dissolving solvents and salt concentrations (3-7 M).
Solution Approach 2:
The patent creates a composite electrolyte system combining multiple components: salt-dissolving solvents (phosphates, phosphonates, sulfones, carbonates), salts (LiPF6, LiBF4, LiTFSI, etc.), and diluents (fluorinated compounds). This composite approach achieves both safety (nonflammability) and performance (ionic conductivity) by synergistic interaction of components.
2Reliability
If conventional liquid electrolytes are used, then electrochemical activity is maintained, but thickness changes exceed 400% during overcharging
Solution Approach 1:
The patent uses high-concentration salt solutions (3-7 M) in high-boiling-point solvents to change the electrolyte's physical parameters, resulting in reduced expansibility and improved thickness stability during overcharging compared to conventional dilute electrolytes.
3Reliability
If conventional liquid electrolytes are used, then ion transport is enabled, but temperature increases lead to thermal runaway during penetration
Solution Approach 1:
The patent changes the thermal parameters of the electrolyte by using solvents with high boiling points (>150°C) and high flash points, which fundamentally alters the temperature profile during abuse conditions like penetration, preventing thermal runaway while maintaining ion transport through appropriate salt and solvent selection.
Solution Approach 2:
The patent converts the potential harm of high temperature during penetration into a benefit by using inherently thermally stable high-boiling-point solvents that raise the temperature threshold for thermal runaway, allowing the battery to withstand penetration events without catastrophic failure.
4Reliability
If nonflammable solvents with high boiling points are used, then safety is improved, but viscosity increases and ionic conductivity decreases
Solution Approach 1:
The patent introduces diluents (fluorinated ethers, esters, carbonates, hydrocarbons) as intermediary substances that mediate between the high-viscosity nonflammable solvents and the salt, reducing overall viscosity and improving ionic conductivity while maintaining the safety benefits of the nonflammable solvent system.
Solution Approach 2:
The patent creates a composite solvent system combining salt-dissolving solvents (high-boiling nonflammable) with diluents (fluorinated compounds), where each component contributes specific properties: the salt-dissolving solvent provides safety and ion solvation, while the diluent provides low viscosity and enhanced 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 system reduces flammability and thermal runaway risks, maintaining stability and safety by minimizing thickness changes and temperature increases during overcharging and penetration.
Implementation Method 1
a polymer precursor (1-20 wt %) to form a gel-polymer electrolyte
Implementation Method 2
a salt (e.g., LiPF6, LiBF4, LiTFSI, LiDFOB, LiBOB) at high concentrations (3-7 M) in the nonflammable or high BP solvent
Implementation Method 3
a diluent to lower viscosity and effective salt concentration while preserving solvation structure of the salt within the nonflammable or high BP solvent
Implementation Method 4
a crosslinking monomer (1-20 wt %) such as an oligomer resin
Data Source
AI summary
A polymer-forming electrolyte can include polymer precursor(s), optional additive(s) (e.g., plasticizers; initiator; inhibitor; performance additives and/or safety additives such as nonflammable additives, flame-retardant additives, redox shuttle additives, SEI-forming additives, SEI-stabilizing additives, self-closing electrolyte additives, etc.; etc.), solvent(s) (e.g., polar solvent; salt-dissolving solvent; salt-coordinating solvent; diluent; safety solvent such as nonflammable solvent, noncombustible solvents, etc.; etc.), and/or salt(s). In some variants, the polymer-forming electrolyte can be cured (e.g., within a battery cell) to form a gel-electrolyte (e.g., between an anode and cathode of the battery cell, interspersed within the anode and the cathode, etc.).