Internal Current Limiter and Interrupter for Battery Thermal Runaway
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Solution Overview
Problem
Lithium-ion batteries face safety hazards due to thermal runaway caused by internal short circuits and overcharging, leading to potential fires or explosions, as they lack effective mechanisms to limit internal discharge rates and interrupt dangerous electrical coupling.
Innovation Solution
Incorporating a current limiter with resistive properties and a thermally or voltage-activatable current interrupter into the battery design to impede current flow and disconnect electrical coupling between electrodes, thereby reducing joule heat generation and preventing thermal runaway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high energy density rechargeable batteries are used to store and deliver large amounts of electrical energy, then the energy storage capacity is improved, but the risk of thermal runaway and safety hazards increases
Solution Approach 1:
A current interrupter device is introduced as an intermediary component between the electrodes and external circuit. This device includes a separator that can transition from a conductive state to a non-conductive state, interrupting current flow when thermal runaway conditions are detected. The interrupter acts as a mediator that protects the high energy density battery system without reducing its energy storage capacity.
Solution Approach 2:
The current interrupter is designed to activate before thermal runaway can cause catastrophic failure. By detecting early signs of thermal runaway (such as temperature increase or voltage changes) and preemptively interrupting the current flow, the system prevents the harmful thermal runaway process from completing, thereby protecting the battery while maintaining its high energy density characteristics.
2Productivity
If internal short circuits occur in lithium-ion batteries, then rapid internal discharge and joule heat generation occur, but the battery lacks mechanisms to limit discharge rates or interrupt electrical coupling
Solution Approach 1:
The separator in the current interrupter transitions from a conductive state during normal operation to a non-conductive state when thermal runaway conditions occur. This dynamic change in electrical properties allows the battery to maintain high discharge rates during normal use while automatically limiting current flow and reducing joule heat generation when internal short circuits occur.
Solution Approach 2:
The current interrupter is designed to automatically detect and respond to thermal runaway conditions without external intervention. The separator's transition from conductive to non-conductive state is triggered by conditions within the battery itself (temperature, voltage), allowing the system to self-regulate and protect against excessive joule heat generation from internal short circuits.
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 effectively diminishes the risk of thermal runaway by slowing internal discharge rates and interrupting electrical coupling, thereby enhancing the safety and reliability of high energy density rechargeable batteries.
Implementation Method 1
the resistive layer configured to limit the rate of internal discharge through the separator in the event of separator failure and the generation of joule heat resulting therefrom
Implementation Method 2
the interrupt layer including a temperature sensitive decomposable component for decomposing upon exposure to temperature at or above the upper temperature safety limit, the temperature sensitive decomposable component for evolving a gas upon decomposition
Implementation Method 3
the evolved gas for delaminating the interrupt layer for interrupting current through the high energy density rechargeable battery
Data Source
AI summary
A high energy density rechargeable (HEDR) battery employs a combined current limiter/current interrupter to prevent thermal runaway in the event of internal discharge or other disruption of the separator. The combined current limiter/current interrupter is interior to the battery.