Low-Temperature Gel Electrolyte for Battery Thermal Runaway Control
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Solution Overview
Problem
Existing in-situ gel electrolytes require high temperatures for polymerization, leading to decomposition of electrolyte solution additives and poor thermal stability, failing to effectively prevent thermal runaway and gas diffusion in batteries.
Innovation Solution
A low-temperature polymerized gel electrolyte is developed using a combination of monofunctional acrylate, polyfunctional acrylate, and functional monomers with cross-linking groups, allowing in-situ polymerization below 40°C, which prevents additive decomposition and enhances electrical performance while thermally curing to maintain separator integrity during thermal runaway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If in-situ polymerization is performed at high temperature (over 60°C), then the degree of polymerization increases and unreacted monomers are consumed, but electrolyte solution additives decompose and lose activity, causing electrolyte discoloration and degraded electrochemical performance
Solution Approach 1:
The patent changes the polymerization temperature parameter from conventional high temperature (over 60°C) to low temperature (not exceeding 40°C). This parameter change prevents decomposition of electrolyte solution additives while still achieving effective polymerization through optimized monomer and initiator selection, thereby maintaining electrochemical performance without additive degradation
Solution Approach 2:
The patent uses a composite gel electrolyte system combining polymer gel matrix with electrolyte solution additives. This composite structure allows the polymer network to form at low temperature without compromising the stability and functionality of the electrolyte additives, resolving the contradiction between polymerization efficiency and additive stability
2Object-affected harmful factors
If conventional gel electrolytes are used, then leakage is limited, but thermal runaway caused by gas diffusion is not significantly improved
Solution Approach 1:
The patent converts the harmful effect of gas generation during thermal runaway into a beneficial outcome by designing the gel electrolyte to thermally close and seal at elevated temperatures. The gas pressure that would normally cause runaway instead triggers the gel's thermal closure mechanism, which seals the separator and prevents further gas diffusion, thereby stopping the thermal runaway process
Solution Approach 2:
The gel electrolyte is designed with pre-established thermal response characteristics that activate before thermal runaway can propagate. The gel's inherent thermal closure property acts as a preemptive safety mechanism, sealing potential gas pathways before dangerous gas diffusion can occur during thermal events
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 gel electrolyte effectively prevents gas diffusion and maintains battery safety by thermally curing during thermal runaway, improving electrical performance and safety without deactivating additives.
Implementation Method 1
immersing the electrode in the precursor solution and performing in-situ polymerization to produce the polymer gel electrolyte/electrode
Implementation Method 2
when early thermal runaway occurs, the gel electrolyte can further thermally cure and become hard, maintaining the integrity of the separator shape and preventing gas diffusion
Data Source
AI summary
Provided in the present invention are a low-temperature polymerized gel electrolyte and a battery comprising same. The raw material for the preparation of the gel electrolyte is a gel precursor solution, and the gel precursor solution comprises polymerization monomers, an electrolyte solution additive, a thermal initiator, a lithium salt and a solvent. By limiting the polymerization monomers to comprise a monofunctional acylate monomer, a polyfunctional acrylate monomer and a functional monomer and further limiting the functional monomer to contain a cross-linking group and a monovinyl group, the gel precursor solution can be polymerized at a relatively low temperature to obtain a gel electrolyte having a soft and sticky texture, such that the decomposition of the electrolyte solution additive added in the gel electrolyte can be avoided, and the electrical performance and safety performance of a battery containing the gel electrolyte are effectively improved.