Internal Temperature Estimation via Impedance Spectroscopy
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Solution Overview
Problem
Current methods for monitoring internal temperatures of electrochemical devices, such as batteries, are inaccurate due to poor thermal conductivity and difficulty in embedding temperature sensors, leading to inefficient and unsafe management of these systems.
Innovation Solution
A method that estimates internal temperature by exciting the device with a driving profile, acquiring voltage and current data, calculating an impulse response, and using a temperature-impedance-state-of-charge relationship to determine the internal temperature without the need for auxiliary temperature sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If thermocouples are embedded into the electrochemical device to measure internal temperature, then internal temperature measurement is achieved, but the device complexity and difficulty of installation increase significantly
Solution Approach 1:
The patent replaces physical temperature sensors (thermocouples) with an electrical measurement system. By measuring impedance changes in the electrochemical device, the system indirectly determines internal temperature without mechanical sensor embedding. The impedance measurement system includes a current source, voltage sensor, and processor that work together to extract temperature information from electrical properties.
Solution Approach 2:
The patent introduces impedance as an intermediary parameter to bridge the gap between electrical measurements and temperature information. Instead of directly measuring temperature with physical sensors, the system measures impedance changes that correlate with temperature variations, using impedance as a mediator to obtain internal temperature data.
2Measurement precision
If infrared imaging is used to measure temperature, then non-contact thermal imaging is achieved, but internal temperature quantification remains difficult and equipment complexity increases
Solution Approach 1:
The patent replaces infrared imaging equipment with a simple electrical measurement system. Instead of using an IR camera to detect thermal radiation, the system uses electrical impedance measurements to infer temperature, substituting complex optical equipment with straightforward electrical circuits and processors.
Solution Approach 2:
The patent creates an electrical copy of temperature information through impedance measurements. Rather than directly observing thermal radiation with IR cameras, the system captures temperature data indirectly through electrical property changes, creating an electrical representation of thermal state.
3Ease of operation
If surface temperature is measured instead of internal temperature, then measurement simplicity is maintained, but temperature accuracy deteriorates due to poor thermal conductivity
Solution Approach 1:
The patent replaces physical temperature sensing with electrical impedance measurement to overcome thermal conductivity limitations. Since electrical signals can penetrate the device structure without being affected by poor thermal conduction, impedance measurements provide direct access to internal temperature information without the accuracy loss inherent in surface measurements.
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 approach provides accurate, real-time internal temperature monitoring, enhancing the safety and efficiency of electrochemical device management by directly extracting temperature information from impedance data, thus overcoming the limitations of conventional surface temperature measurements.
Implementation Method 1
calculating an impedance spectrum of the electrochemical device from the impulse response using an impulse response model; estimating an internal temperature of the electrochemical device based on a temperature-impedance-state-of-charge relationship characterizing the electrochemical device
Data Source
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AI summary
The internal temperature of an electrochemical device may be probed without a thermocouple, infrared detector, or other auxiliary device to measure temperature. Some methods include exciting an electrochemical device with a driving profile; acquiring voltage and current data from the electrochemical device, in response to the driving profile; calculating an impulse response from the current and voltage data; calculating an impedance spectrum of the electrochemical device from the impulse response; calculating a state-of-charge of the electrochemical device; and then estimating internal temperature of the electrochemical device based on a temperature impedancestate-of-charge relationship. The electrochemical device may be a battery, fuel cell, electrolytic cell, or capacitor, for example. The procedure is useful for on-line applications which benefit from real-time temperature sensing capabilities during operations. These methods may be readily implemented as part of a device management and safety system.