Internal Battery Current Limiter and Interrupter for Thermal Runaway
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Solution Overview
Problem
Lithium-ion batteries are prone to thermal runaway due to internal short circuits and overcharge, which can lead to fire or explosion, necessitating a solution to limit and interrupt internal current to prevent such events.
Innovation Solution
A high energy density rechargeable battery with integrated current limiters and interrupters that resistively impede current flow and delaminate at trigger conditions to form nonconductive gaps, reducing joule heat and preventing thermal runaway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high energy density battery systems are used to store and deliver large amounts of electrical energy, then 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 requiring fundamental changes to the battery chemistry.
Solution Approach 2:
The current interrupter is designed to preemptively counteract thermal runaway before it can develop into a hazardous event. Temperature sensors and pressure sensors detect early signs of thermal runaway, and the separator transitions to a non-conductive state in advance, preventing the full development of the thermal runaway chain reaction. This preliminary anti-action stops the harmful process before it can cause fire or explosion.
2Power
If internal current is allowed to flow freely in the battery, then power delivery is improved, but the risk of internal short circuit and thermal runaway increases
Solution Approach 1:
The separator in the current interrupter is designed with dynamic properties that allow it to change its electrical conductivity based on operating conditions. Under normal conditions, the separator maintains good electrical contact, allowing high current flow for power delivery. When temperature or pressure thresholds are exceeded, the separator dynamically transitions to a non-conductive state, automatically interrupting current flow to prevent internal short circuits and thermal runaway.
Solution Approach 2:
The electrical conductivity parameter of the separator is made changeable in response to temperature and pressure changes. The separator material is selected or designed to undergo a phase transition or resistance change at specific temperature thresholds. This parameter change allows the system to maintain high power delivery during normal operation while automatically limiting current when thermal runaway conditions develop.
3Reliability
If overcharge protection is implemented to prevent thermal runaway, then safety is improved, but charging speed and energy input rate are limited
Solution Approach 1:
The current interrupter system provides self-service overcharge protection without requiring external monitoring or control systems. The separator's intrinsic properties cause it to automatically transition to a non-conductive state when voltage-induced temperature or pressure thresholds are exceeded. This self-service mechanism protects the battery from overcharge while maintaining high charging speeds during normal operation, as no active control or current limiting is needed until the safety threshold is reached.
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 limits and interrupts internal discharge, reducing the risk of thermal runaway and ensuring safety by slowing the rate of discharge and delaminating at trigger conditions.
Implementation Method 1
The gas generating component can have a trigger for generating a gas, the trigger being selected from the group consisting of temperature triggers and voltage triggers
Implementation Method 2
The current interrupter transitions from the engaged to the disengaged configuration by triggering the gas generating component responsive to the trigger, the generated gas delaminating the laminated connection
Implementation Method 3
the current limiter having a resistivity for resistively impeding current therethrough and, in the event the separator forms the short circuit, for diverting current
Implementation Method 4
for slowing the rate of internal discharge resulting from the short circuit, for slowing the production of joule heat therefrom
Implementation Method 5
in the engaged configuration, the current interrupter electrically coupling one of the electrodes and its corresponding current collector with a laminated connection
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.