Polyether Urethane Polymer for Lithium Battery Overcharge Safety
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Solution Overview
Problem
Conventional lithium secondary batteries are prone to ignition and explosion due to overcharge, high temperatures, and external damage, with existing safety measures either requiring additional installation or compromising battery performance.
Innovation Solution
Incorporating a polyether urethane polymer into the electrodes, which decomposes upon overcharge, increasing internal resistance and providing time delay effects to prevent abnormal battery operation, while maintaining minimal adverse effects on general performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If external safety devices (PTC, CID, protection circuits) are added to the battery, then battery safety is improved, but device complexity and installation requirements increase
Solution Approach 1:
The patent combines the safety function with the electrode material itself by incorporating polyether urethane polymer into the electrode structure. This merging eliminates the need for separate external safety devices while maintaining protective functions, directly resolving the contradiction between safety and device complexity
Solution Approach 2:
The electrode material performs self-protection through the polyether urethane polymer that automatically responds to abnormal conditions (overcharge, high temperature) by decomposing and increasing resistance. This self-service mechanism eliminates the need for external monitoring and control systems, reducing installation complexity while ensuring safety
2Reliability
If chemical additives are added to electrolytes or electrodes to improve safety, then battery safety is improved, but manufacturing precision and performance stability deteriorate
Solution Approach 1:
The patent uses polyether urethane polymer as a composite material integrated into the electrode structure. This composite approach provides reliable safety performance through controlled decomposition characteristics while maintaining manufacturing precision, as the polymer is incorporated as a defined component rather than mixed additive
Solution Approach 2:
The polyether urethane polymer responds to abnormal conditions by changing its physical-chemical parameters (decomposition, resistance increase). This parameter change mechanism provides predictable safety responses that maintain performance stability, unlike uncontrolled chemical additives
3Reliability
If materials that undergo polymerization under overcharge conditions are added to electrolytes, then battery safety is improved, but manufacturing precision deteriorates due to performance deterioration
Solution Approach 1:
Instead of using materials that polymerize under overcharge conditions (which can cause performance issues), the patent employs polyether urethane polymer that decomposes under overcharge conditions. This inverted approach provides overcharge protection while avoiding the performance deterioration associated with polymerization
Solution Approach 2:
The patent utilizes parameter changes through decomposition rather than polymerization. The polyether urethane polymer decomposes under overcharge conditions to increase resistance and stop the reaction, providing protection without the performance deterioration that can result from polymerization of electrolyte additives
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 polyether urethane polymer effectively enhances overcharge safety by delaying abnormal battery operation and increasing internal resistance, thereby preventing ignition and explosion without significant deterioration of battery performance.
Implementation Method 1
the thus-added polymer decomposes upon overcharge of the battery, thereby obtaining the time delay effects for securing battery safety
Implementation Method 2
the decomposition products thereof result in increased internal resistance of the battery, thereby increasing battery safety
Data Source
Figure 1
AI summary
Disclosed is a lithium secondary battery comprising an electrode assembly composed of a cathode, an anode and a separator, and a lithium electrolyte, wherein the electrodes and/or electrolyte include a compound ("urethane compound") and/or polymer ("poly urethane") which are decomposed upon overcharge of the battery and contain a urethane group in a molecular structure thereof. The lithium secondary battery of the present invention is characterized by addition of a compound or polymer having a urethane group to electrodes and/or electrolyte, wherein the thus-added compound and/or polymer have substantially no adverse effects on general performance of the battery under normal operating conditions and are decomposed with high reliability upon overcharge of the battery, thereby offering time delay effects for securing battery safety, and the decomposition products thereof result in sharply increased internal resistance of the battery, thereby increasing battery safety.