Battery Thermal Interface Fault Detection
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Solution Overview
Problem
Current thermal conditioning systems in electric and hybrid vehicles face reliability issues due to degradation of thermal interfaces, leading to inefficient heat exchanges and potential damage to lithium-ion batteries, with existing fault detection methods unable to accurately diagnose faults outside the battery.
Innovation Solution
A method that evaluates the thermal resistance of all interfaces involved in thermal conditioning, using a heat exchange model to compare measured and estimated battery temperatures, detecting any degradation and signaling overrun, which can be implemented during vehicle maintenance or driving, and involves a heat transfer fluid circuit with thermal resistances of the battery, sole, and pad.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thermal conditioning system is used to maintain battery temperature, then battery performance and lifespan are improved, but the reliability of thermal interfaces degrades over time due to mechanical characteristic changes
Solution Approach 1:
The system performs preliminary thermal conditioning of the battery and measures temperatures before comparing them with model predictions. This preliminary action allows detection of thermal interface faults before they cause significant performance degradation, enabling preventive maintenance rather than reactive repair.
Solution Approach 2:
The system continuously monitors battery temperature during thermal conditioning, compares measured temperatures with expected temperatures from a thermal model, and uses this feedback to detect deviations indicating thermal interface faults. This closed-loop feedback mechanism enables real-time assessment of thermal interface health throughout the vehicle's service life.
2Difficulty of detecting and measuring
If existing fault detection methods are used, then some cooling system faults can be diagnosed, but faults at interfaces outside the battery cannot be detected
Solution Approach 1:
The thermal conditioning system is divided into discrete thermal zones with temperature measurements taken at multiple locations (battery inlet, outlet, and ambient). This segmentation allows identification of which specific thermal interface has degraded, providing precise localization of faults outside the battery rather than generic system-wide diagnostics.
Solution Approach 2:
A thermal model serves as an intermediary between the physical thermal conditioning system and the diagnostic system. The model predicts expected temperature distributions, and deviations between predicted and measured temperatures indicate thermal interface faults. This intermediary approach enables indirect detection of interface faults that cannot be directly measured.
3Productivity
If thermal interface faults are not detected, then the system continues operating, but energy overconsumption occurs and battery performance degrades
Solution Approach 1:
The system uses feedback from temperature measurements and thermal model comparisons to detect when thermal interfaces are degrading. Once a fault is detected, the system can alert operators to perform maintenance, preventing the progression to states of severe energy overconsumption while allowing continuous operation during the early fault detection phase.
Solution Approach 2:
By detecting thermal interface faults early through preliminary temperature measurements and model comparisons, the system enables timely maintenance interventions before energy overconsumption becomes significant. This preliminary detection prevents the accumulation of energy losses that would occur if faults went undetected until severe degradation.
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
This method effectively detects thermal interface faults, reducing energy overconsumption, maintaining battery performance, and extending vehicle autonomy while allowing for timely mechanical realignments to correct interface defects.
Implementation Method 1
a model of the heat exchanges between the battery and the conditioning system
Implementation Method 2
a circuit in which a heat transfer fluid circulates
Data Source
Figure 1~2
AI summary
The present invention relates to a method for detecting a thermal interface defect between a battery and its thermal conditioning system. The method includes a step of thermally conditioning the battery using the conditioning system. It also includes, at the end of the conditioning step, a step of measuring a temperature value representative of the battery temperature. It further includes a step of estimating, using a model of the heat exchange between the battery and the conditioning system, an expected battery temperature at the end of the conditioning step. It also includes a step of comparing the measured temperature with the estimated temperature. Finally, if the difference between the measured temperature and the estimated temperature exceeds a predetermined threshold, it includes a step of storing or making available information indicating that the threshold has been exceeded.Application: electric or hybrid vehicles, aeronautics.