Composite Salt Layer for Lithium Battery Thermal Runaway Suppression
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Solution Overview
Problem
Current methods for suppressing thermal runaway in lithium batteries are inadequate as they primarily focus on single aspects and lack a fast, high-efficiency, multi-aspect solution, leading to potential fires or explosions due to uncontrolled heat reactions.
Innovation Solution
A thermal runaway suppression element with a composite salt layer, composed of a eutectic mixture of inorganic salts with a melting point between 90 to 150°C, which reacts with the electrochemical system to form passivation layers, reduce state of charge, and decrease ionic and electronic conductivity by etching the aluminum current collecting layer and polymerizing the electrolyte.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single aspect suppression method (physical, chemical, or electrochemical) is used inside the battery cell, then the device complexity is reduced, but the thermal runaway suppression effectiveness is insufficient
Solution Approach 1:
The patent combines multiple suppression mechanisms (physical shutdown via separator closure, chemical flame retardant action, and electrochemical reaction type suppression) into a single integrated suppression element that can simultaneously perform multiple functions when thermal runaway occurs
Solution Approach 2:
The suppression element is designed to provide multi-aspect thermal runaway suppression through a single component, enabling it to perform physical blocking, chemical flame retardancy, and electrochemical suppression functions universally across different thermal runaway scenarios
2Reliability
If the melting point of the composite salt layer is set between 90 to 150°C, then the suppression activation temperature is optimized for early thermal runaway detection, but the risk of premature activation under normal operating conditions increases
Solution Approach 1:
The patent optimizes the melting point parameter of the composite salt layer to a specific range (90-150°C) that balances early detection capability with avoidance of premature activation, representing a carefully selected parameter change to resolve the contradiction
3Reliability
If the composite salt layer etches the aluminum current collecting layer to reduce SOC, then the thermal runaway suppression effectiveness is improved, but the battery capacity is reduced
Solution Approach 1:
The patent converts the potentially harmful effect of aluminum current collector etching (which would normally be considered damage) into a beneficial suppression mechanism by utilizing the etching reaction to reduce SOC and terminate thermal runaway, thereby transforming a harmful process into a protective function
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
Effectively terminates thermal runaway events by synchronizing multiple suppression mechanisms, reducing the risk of fires or explosions in lithium batteries through the formation of passivation layers and decreased conductivity, enhancing safety.
Implementation Method 1
The composite salt layer has a melting point between 90 to 150° C.
Implementation Method 2
The SOC (state of charge) is reduced due to the etching of the aluminum current collecting layer by the thermal runaway suppression element in the molten state
Implementation Method 3
The active materials will become thermodynamically stable (i.e., inert or inactive) from a state with higher released thermal energy to a state with lower released thermal energy
Implementation Method 4
The liquid, gel or jelly electrolyte is polymerized and carbonized to block ion transport
Implementation Method 5
The liquid, gel or jelly electrolyte is polymerized and carbonized to block ion transport
Data Source
AI summary
This invention provides a thermal runaway suppression element for lithium batteries and the related applications. The thermal runaway suppression element includes a composite salt layer provided by a eutectic mixture containing at least two single inorganic salts. The composite salt layer has a melting point between 90 to 150° C. At least one of the single inorganic salts comprises a cation, which is an amphoteric metal ion or an alkali metal ion. The thermal runaway suppression element is disposed inside or outside the lithium battery. When the temperature of the lithium battery reaches to 90 to 150° C., the composite slat layer will be molten and reacts with the electrochemical reaction system to passivate the active materials and decrease ionic and electronic conductivity. Therefore, the thermal runaway event and its derived problem are efficiently solved.