Battery Cell Overheating Detection via Temperature Gradient Monitoring
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Solution Overview
Problem
Current methods for detecting imminent overheating in battery cells, particularly in high-voltage batteries, often require exceeding a critical temperature limit, leading to false alarms and delayed detection, as operating conditions like rapid charging can cause high temperatures without actual overheating.
Innovation Solution
The method involves detecting imminent overheating by monitoring temperature gradients and cell voltages over time, allowing for earlier identification of potential overheating before the absolute temperature reaches critical levels, using sensors to determine these variables and compare them with specified limits to initiate warnings or countermeasures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a predetermined critical temperature limit is used for detecting overheating, then the detection system is simple to operate, but the detection occurs too late and produces false alarms during rapid charging or high-performance driving
Solution Approach 1:
The system performs preliminary detection by monitoring temperature gradients before the absolute temperature reaches critical levels. The control unit calculates the rate of temperature change and compares it against threshold values, enabling early warning of imminent overheating before actual thermal damage occurs.
Solution Approach 2:
The invention changes the monitoring parameter from absolute temperature to temperature gradient (rate of temperature change). This parameter transformation allows the system to detect thermal propagation earlier, distinguishing between normal temperature increases during charging and dangerous rapid heating that indicates cell failure.
2Reliability
If the critical temperature threshold is reduced to enable earlier detection, then detection timing improves, but false alarms increase during normal high-temperature operation
Solution Approach 1:
The system transforms the detection parameter from static absolute temperature to dynamic temperature gradient. This allows the system to recognize the pattern of thermal propagation (rapid temperature increase) versus normal operating temperature variations, eliminating false alarms while maintaining high detection sensitivity.
Solution Approach 2:
The control unit continuously monitors temperature gradients and provides feedback by comparing measured values against threshold limits. When the temperature gradient exceeds the threshold, the system triggers a warning signal, creating a closed-loop monitoring system that adapts to real-time thermal conditions.
3Ease of operation
If absolute temperature monitoring is used, then the measurement is straightforward, but thermal propagation cannot be detected until temperatures reach dangerous levels
Solution Approach 1:
The system changes the measured parameter from absolute temperature to temperature gradient (rate of change). The control unit calculates dT/dt by comparing temperature measurements over time intervals, enabling detection of rapid thermal propagation while maintaining operational simplicity through automated calculation.
Solution Approach 2:
The invention replaces direct thermal measurement with a derived measurement system. Instead of relying solely on absolute temperature sensors, the system uses temporal differentiation of temperature data to detect thermal propagation, substituting a more sophisticated measurement approach for the simpler but less accurate absolute temperature monitoring.
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 a significantly earlier detection of overheating, extending the time for operator warnings and system disabling, enhancing safety by giving drivers more time to safely park the vehicle and preventing potential dangers like thermal propagation and fires.
Implementation Method 1
a temperature gradient over time of a temperature sensed in a predetermined proximity to the at least one battery cell
Implementation Method 2
a voltage of the at least one battery cell
Implementation Method 3
this temperature increase is transferred by thermal conduction to other cells of the battery system
Data Source
AI summary
A method for detecting an imminent overheating of at least one battery cell of a battery, preferably for a motor vehicle. The imminent overheating is detected as a function of at least one determined first variable relating to the at least one battery cell. A temperature gradient over time of a temperature sensed in a predetermined proximity to the at least one battery cell and/or a voltage of the at least one battery cell is determined as the at least one first variable.