Lithium Battery Safety Vent and Electrolyte Additives
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Solution Overview
Problem
Conventional lithium secondary batteries face issues with excessive gas generation during overcharging, leading to potential explosions or ignitions, and existing safety vents are overly sensitive, causing environmental hazards even when there is no danger.
Innovation Solution
A lithium secondary battery design incorporating a non-aqueous electrolyte solution with a mixture of toluene and xylene as additives, which inhibits decomposition and forms a coating film to prevent gas generation, combined with a safety vent having a controlled opening pressure range of 343.2 to 1471 kPa to prevent unnecessary vent operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the safety vent is made highly sensitive to internal pressure, then it can effectively prevent explosion and ignition by venting gas early, but it causes unnecessary vent opening and environmental pollution during normal operation
Solution Approach 1:
The patent changes the pressure parameter threshold for vent opening from a low sensitive value to a specifically controlled range of 343.2 to 1471 kPa. This parameter adjustment ensures the vent only opens when internal pressure reaches dangerous levels, preventing both premature opening during normal operation and failure to open during actual danger, thereby resolving the contradiction between safety effectiveness and environmental protection
2Use of energy by moving object
If the battery uses conventional non-aqueous electrolyte, then it achieves high energy density, but it generates excessive gas during overcharging leading to safety hazards
Solution Approach 1:
The patent introduces a specific non-aqueous electrolyte composition containing cyclic carbonate and chain carbonate as intermediary substances that mediate between the electrodes and prevent excessive gas generation during overcharging. This electrolyte system maintains high energy density while acting as a buffer that suppresses harmful gas production, resolving the contradiction between energy density and safety
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 minimizes gas generation and prevents premature vent opening, ensuring battery safety during overcharging and reducing environmental pollution, while maintaining effective pressure relief when necessary.
Implementation Method 1
a non-aqueous solution containing toluene-based and xylene-based additives to minimize gas generation at a high temperature, thereby preventing the internal pressure of the battery from being raised
Implementation Method 2
inhibits decomposition and forms a coating film to prevent gas generation
Implementation Method 3
a safety vent for removing increased internal pressure, wherein the safety vent has a vent hole whose opening pressure is in the range of 343.2 to 1471 kPa
Data Source
AI summary
The present invention provides a lithium secondary battery, comprising a cathode, an anode, a non-aqueous solution containing a lithium salt and an organic solvent, and a safety vent for removing increased internal pressure, the non-aqueous solution having the prescribed composition and the safety vent having the prescribed operational characteristics. The lithium secondary battery of the present invention can ensure its safety even when overcharged.