FSR Battery Vent Pressure Sensing for Early Thermal Runaway Detection
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Solution Overview
Problem
Current detection methods for thermal runaway conditions in rechargeable automotive traction batteries are complex and fail to detect the issue early enough to prevent smoke or fire outbreaks within the vehicle compartment.
Innovation Solution
A detection device utilizing a force-sensing resistor (FSR) with flexible substrates and a venting duct, connected to a safety relief valve, which detects pressure changes caused by gas flow during thermal runaway, triggering a sharp resistance drop when predefined pressure thresholds are exceeded, allowing for early detection of thermal runaway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple sensors (voltage, gas, smoke, temperature, pressure) are used for thermal runaway detection, then detection reliability is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple detection functions into a single integrated sensor unit. The sensor housing integrates the force-sensing resistor, venting duct, and detection region into one compact component that simultaneously monitors pressure changes, gas flow, and thermal conditions, thereby achieving multi-parameter detection without proportionally increasing device complexity
Solution Approach 2:
The sensor housing serves multiple functions: it acts as a structural component of the battery pack, a detection chamber for thermal runaway indicators, a flow path for gas venting, and a mounting structure for the force-sensing resistor. This multi-functionality reduces the need for separate components and simplifies the overall detection system
2Reliability
If detection is performed early before smoke or fire, then safety is improved, but detection difficulty increases due to subtle early-stage signals
Solution Approach 1:
The patent places the detection region and force-sensing resistor in close proximity to the battery cells and thermal runaway sources. By concentrating the sensing elements at the critical location where early pressure changes and gas flow occur, the sensor can detect subtle early-stage indicators with high sensitivity before they propagate to visible smoke or fire
Solution Approach 2:
The venting duct acts as an intermediary channel that amplifies early-stage pressure changes and directs gas flow toward the detection region. This intermediary structure enhances the detectability of subtle thermal runaway signals by concentrating and channeling the physical indicators toward the sensing elements
3Volume of moving object
If a compact sensor design is used, then space utilization is improved, but manufacturing precision requirements increase
Solution Approach 1:
The sensor housing is designed as a segmented modular structure with distinct sections for the force-sensing resistor, venting duct, and detection region. This segmentation allows each component to be manufactured and calibrated separately with standard tolerances, then assembled into the compact final product, reducing the cumulative precision requirements compared to a monolithic design
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 provides a low-complexity, reliable detection of thermal runaway conditions before fire or smoke occurs, ensuring passenger safety by using simple electronics and a space-saving design within the battery housing.
Implementation Method 1
a force-sensing resistor (FSR) pressure sensor... which detects pressure changes caused by gas flow during thermal runaway, triggering a sharp resistance drop when predefined pressure thresholds are exceeded
Implementation Method 2
a venting duct connecting a space between the two substrates and a vent outlet of the force-sensing resistor... The vent outlet is fluidically connectable to a detection region
Data Source
AI summary
A detection device for detecting a thermal runaway condition in a rechargeable automotive traction battery that includes a closed traction battery housing for receiving at least a plurality of rechargeable electrochemical energy cells and being equipped with a safety relief valve. The detection device includes a force-sensing resistor. The force-sensing resistor has flexible substrates separated by a spacer member and defining a force-sensitive area, and a venting duct connecting a space between the two substrates and a vent outlet. At least the force-sensitive area of the force-sensing resistor is placeable inside the traction battery housing, and the vent outlet is fluidically connectable to a detection region of an interior space of the traction battery housing which is located in the vicinity of the safety relief valve.