Non-aqueous electrolyte additive for battery swelling
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Solution Overview
Problem
Conventional non-aqueous electrolytes in secondary batteries form weak and thermally unstable SEI layers, leading to battery swelling and capacity reduction at high temperatures, posing safety risks and performance degradation.
Innovation Solution
Incorporating a compound with both a carboxy group and a (meth)acrylic group as an electrolyte additive, which forms a thermally stable SEI layer on the anode surface, reducing swelling and enhancing battery performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional electrolyte solvent (carbonate-based organic solvent) is used to form an SEI layer on the anode surface, then the SEI layer can prevent decomposition of the electrolyte and structural collapse of the electrode, but the SEI layer is weak, porous, and thermally unstable, leading to breakdown at high temperatures and subsequent battery swelling
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte by introducing a specific carboxylic acid compound (Formula 1) with defined molecular structure parameters (R1-R6 groups, n value). This compositional parameter change transforms the SEI layer properties, making it thermally stable while maintaining protective function. The carboxylic acid compound reacts to form an SEI layer with different chemical stability parameters compared to conventional carbonate-based solvents.
Solution Approach 2:
The patent creates a composite SEI layer structure by combining the protective function of conventional SEI with the thermal stability of carboxylic acid-derived compounds. The resulting SEI layer integrates multiple functional properties: it maintains the barrier function against electrolyte decomposition while incorporating thermally stable carboxylic acid groups that prevent high-temperature breakdown and battery swelling.
2Reliability
If the SEI layer is formed by conventional electrolyte solvents, then it provides initial protection during charge/discharge, but it breaks down due to electrochemical and thermal energy at high temperatures, causing re-formation of SEI layer and reduction of battery capacity
Solution Approach 1:
The patent applies preliminary action by having the carboxylic acid compound (Formula 1) react during initial battery cycles to form a pre-stabilized SEI layer structure. This preliminary formation process creates a thermally stable protective layer before the battery undergoes high-temperature operation, preventing subsequent SEI breakdown and capacity loss. The carboxylic acid groups are incorporated early to establish long-term stability.
3Productivity
If the SEI layer collapses at high temperatures, then side reactions such as electrolyte decomposition occur on the exposed anode surface, generating gas such as CO2 and causing swelling phenomenon and thickness increase of the battery
Solution Approach 1:
The patent converts the potentially harmful effect of high-temperature operation into a benefit by using the carboxylic acid compound to form an SEI layer that is specifically stable at high temperatures. The carboxylic acid groups (Formula 1) transform the thermal energy that would normally cause SEI breakdown into a stabilizing factor, preventing electrolyte decomposition and gas generation. The thermal stress that would cause swelling is instead used to validate the enhanced thermal stability of the new SEI structure.
4Adaptability or versatility
If other electrolyte additives are combined with the carboxylic acid compound, then various battery performance aspects can be addressed, but the combination may counterbalance or reduce the swelling suppression effect of the carboxylic acid compound
Solution Approach 1:
The patent applies local quality by assigning specific functional roles to different electrolyte components. The carboxylic acid compound (Formula 1) is specifically designated for swelling suppression and thermal stability, while other additives can address different performance aspects (capacity, rate capability, etc.). This functional segmentation allows multiple additives to work in parallel without interfering with the primary swelling suppression mechanism, as each additive operates in its designated functional domain.
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 compound significantly suppresses battery thickness increase at high temperatures, improves capacity recovery, and maintains performance by forming a stable passivation layer that facilitates lithium ion movement, even when used in combination with other additives.
Implementation Method 1
the lithium ion, an electrolyte solvent, an anode active material, etc. may form a sort of SEI (Solid Electrolyte Interface) layer on the surface of the anode active material through a reaction
Implementation Method 2
lithium ions deintercalated from a cathode active material upon the first charge cycle are intercalated into an anode active material
Implementation Method 3
lithium ions reciprocate between both electrodes while transferring energy
Data Source
Figure 1~2
AI summary
Disclosed is a non-aqueous electrolyte including an electrolyte salt and an electrolyte solvent, the non-aqueous electrolyte further including a compound containing both a carboxy group and a (meth)acrylic group, and a secondary battery including the non-aqueous electrolyte. The use of the compound containing both the carboxy group and the (meth)acrylic group as a component for an electrolyte significantly reduces the increase of battery thickness at high temperature storage.