Battery Tab Sealing and Electrolyte Composition for High-Temperature Gassing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lithium-ion batteries face safety issues in high-temperature and high-humidity environments due to gassing phenomena and oxidative decomposition of the electrolyte solution, leading to potential combustion risks.
Innovation Solution
An electrochemical device with a specific composition of electrolyte solution constituents, including non-fluorinated cyclic carbonate, fluorinated cyclic carbonate, carboxylate, and linear carbonate, along with controlled tab adhesive thickness, to reduce gassing and enhance sealing, thereby improving storage safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tensile sealing force of the battery is increased to block external moisture, then the sealing performance is improved, but the internal gas cannot be released and heat accumulation occurs leading to safety hazards
Solution Approach 1:
The patent changes the chemical composition parameters of the electrolyte solution by replacing part of the traditional carbonate solvent (EC, PC, DEC, DMC) with cyclic carboxylate (GBL, GVL) and chain carboxylate (DMF, NMP). This parameter change in solvent composition fundamentally alters the electrochemical behavior, suppressing oxidative decomposition reactions that generate gas, thereby resolving the contradiction between sealing performance and heat accumulation prevention
Solution Approach 2:
The patent creates a composite electrolyte system combining multiple solvent types (cyclic carbonate, chain carbonate, cyclic carboxylate, chain carboxylate) with specific mass ratios. This composite approach leverages the complementary properties of different solvents to achieve both effective sealing and safe gas management by reducing gassing while maintaining electrochemical performance
2Object-generated harmful factors
If positive electrode additive is added to suppress oxidative decomposition, then the gassing phenomenon is alleviated, but it is hardly effective in high-temperature and high-humidity environment
Solution Approach 1:
The patent fundamentally changes the electrolyte composition parameters by introducing cyclic carboxylate (γ-butyrolactone, γ-valerolactone) and chain carboxylate (dimethylformamide, dimethylacetamide) solvents. These compositional changes create an electrolyte system with inherently higher thermal stability and lower gassing tendency, maintaining effectiveness in high-temperature and high-humidity environments where traditional additives fail
Solution Approach 2:
The patent introduces carboxylate compounds as intermediary substances that mediate between the electrode and the electrolyte environment. These carboxylates form stable interfacial layers that suppress oxidative decomposition reactions, acting as effective mediators that prevent gassing under harsh thermal and humid conditions where conventional additives are ineffective
3Reliability
If carbonate solvent is used to form SEI film, then the safety performance is improved, but the gassing phenomenon occurs at high temperature
Solution Approach 1:
The patent develops a composite electrolyte formulation that combines cyclic carbonate, chain carbonate, cyclic carboxylate, and chain carboxylate in optimized mass ratios. This composite system maintains the SEI-forming capability of carbonates while the carboxylate components suppress high-temperature gassing, achieving both safety performance and reduced gassing through synergistic material combination
Solution Approach 2:
The patent optimizes the mass ratio parameters of different solvent components, specifically setting cyclic carboxylate at 10-60 mass% and chain carboxylate at 5-50 mass% of the total electrolyte. These parameter adjustments create an electrolyte composition that forms protective SEI films while minimizing oxidative decomposition and gassing at elevated temperatures
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
Significantly reduces gassing and expansion, prevents hydrofluoric acid generation, and ensures effective sealing, enhancing the safety of lithium-ion batteries in extreme conditions.
Implementation Method 1
a lithium salt (such as LiPF6) is typically dissolved in a solvent to make an electrolyte solution
Implementation Method 2
form a solid electrolyte interface (SEI) film on the surface of an active material. The SEI film can effectively reduce side reactions of the electrolyte solution on the surface of the active material
Implementation Method 3
A tab adhesive is disposed on the tab adhesive coverage region... ensure a good sealing effect of the region sealed by the tab adhesive
Data Source
AI summary
An electrochemical device, including a tab and an electrolyte solution. The tab includes a tab metal strap. The tab metal strap includes a head blank foil region, a tab adhesive coverage region, and an ending connection region along a length direction. A tab adhesive is disposed on the tab adhesive coverage region, and a thickness of the tab adhesive is t mm, satisfying: 0.025≤t≤0.14. The electrolyte solution includes a non-fluorinated cyclic carbonate, a fluorinated cyclic carbonate, a carboxylate, and a linear carbonate.