FSR Battery Housing Pressure Sensing for Early Thermal Runaway Detection
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Solution Overview
Problem
Existing detection methods for thermal runaway in rechargeable automotive traction batteries are complex and often fail to detect the condition in its early stages, potentially leading to fires or smoke inside a vehicle compartment.
Innovation Solution
A detection device utilizing a force-sensing resistor (FSR) with flexible substrates and a venting duct, which can be located inside or outside the traction battery housing, to detect the increased pressure caused by thermal runaway through changes in electrical resistance.
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 (pressure sensing, gas detection, and force measurement) into a single integrated force-sensing resistor device. The FSR structure includes a sensing element, venting duct, and flexible substrate that work together to detect thermal runaway through pressure changes and gas infiltration, eliminating the need for separate sensors and reducing overall system complexity while maintaining high detection reliability
Solution Approach 2:
The force-sensing resistor is designed to perform multiple detection functions simultaneously: it measures internal pressure changes through its sensing element, detects gas infiltration through the venting duct, and monitors force applied by swelling cells. This multi-functional design allows one device to replace what would traditionally require multiple separate sensors, resolving the contradiction between reliability and complexity
2Object-affected harmful factors
If a closed battery housing is used to contain thermal runaway, then safety is improved, but pressure buildup increases detection difficulty
Solution Approach 1:
The venting duct acts as an intermediary element that connects the sealed battery housing interior to the force-sensing resistor. It allows pressure changes and gas infiltration to be transmitted to the FSR sensing element without compromising the sealed containment of the battery housing, thus enabling detection while maintaining safety
Solution Approach 2:
The patent replaces direct mechanical pressure measurement with an electrical resistance-based measurement system. The force-sensing resistor converts pressure-induced mechanical deformation into electrical resistance changes, which are easier to measure and process, thereby reducing detection difficulty while maintaining closed housing benefits
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 detection device allows for early detection of thermal runaway conditions in rechargeable automotive traction batteries, reducing the risk of fires or smoke inside the vehicle compartment by providing a low-complexity, reliable solution.
Implementation Method 1
a single point thin film piezo-resistive force sensor with the range of 0 N≤Fsens≤445 N that is used to measure the force between a cell in thermal runaway and adjacent parts/cells caused by the cell swelling
Implementation Method 2
The detection device includes a force-sensing resistor that comprises at least two flexible substrates being separated by a spacer member and defining a force-sensitive area
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. The detection device includes a force-sensing resistor. The force-sensing resistor has flexible substrates separated by a spacer member and a vent outlet. The vent outlet is fluidically connectable to an exterior space of the traction battery housing if the force-sensing resistor is located inside the traction battery housing. At least one of the flexible substrates is operatively connectable to an interior space of the traction battery housing if the force-sensing resistor is located outside the traction battery housing.