Vehicle Battery Cell Temperature Extrapolation Using Resistance
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Solution Overview
Problem
Existing methods for monitoring the temperature of battery cells in vehicle batteries are complicated and costly due to the need for individual temperature sensors on each cell, and existing computational methods provide irregular values.
Innovation Solution
A method that determines the temperature of multiple battery cells by measuring voltages and currents, calculating resistances, and using a reference resistance and resistance relationships to extrapolate temperatures without individual sensors on all cells, relying on a distribution function or value table for precise temperature determination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a temperature sensor is arranged on each battery cell, then the temperature monitoring precision is improved, but the device complexity and cost increase
Solution Approach 1:
The patent uses electrical resistance as a substitute (copy) for direct temperature measurement. Instead of placing temperature sensors on every battery cell, it measures the internal resistance of each cell, which correlates with temperature, thereby obtaining temperature information indirectly through a simpler measurement process
Solution Approach 2:
The patent replaces the mechanical/physical temperature sensing system with an electrical measurement system. By measuring internal resistance through voltage and current measurements and deriving temperature from resistance-temperature correlations, it substitutes direct thermal measurement with electrical property measurement
2Productivity
If adaptive models like Kalman filter are used to determine temperature, then the computational effort is reduced, but the values provided are irregular
Solution Approach 1:
The patent employs feedback mechanisms where measured temperatures from selected battery cells are used to update and refine the resistance-temperature correlations. This feedback loop allows the system to adapt to changing conditions while maintaining regular and reliable temperature estimates for all cells through continuous correlation updates
Solution Approach 2:
The patent changes the approach from using fixed adaptive models to using measurable electrical parameters (internal resistance) that have known correlations with temperature. By measuring resistance values and applying resistance-temperature correlation data, the system generates regular temperature values without relying on complex adaptive modeling
3Productivity
If internal resistance measurement methods are used, then the computational effort is low, but the values can only be provided irregularly
Solution Approach 1:
The patent merges the internal resistance measurement process with temperature determination. By combining resistance measurements from multiple cells and using correlation data, it creates a unified approach that maintains computational efficiency while ensuring regular temperature value provision through systematic data processing
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 allows for efficient and cost-effective monitoring of battery cell temperatures with reduced sensor usage, providing precise temperature readings across all cells based on measured values and resistance correlations.
Implementation Method 1
An electrical energy storage of a motor vehicle can also be described as a vehicle battery and/or traction battery. A vehicle battery is composed of a plurality of battery cells that are interconnected among each other in series and/or in parallel.
Implementation Method 2
The temperature and/or the degradation of the respective battery cell can in particular be determined from the internal resistance. The internal resistance of a respective battery cell can for example be used by means of a current pulse measuring method that utilises a correlation of a voltage response to a current pulse.
Data Source
AI summary
A method for determining respective temperatures of a plurality of battery cells includes determination of measured values including a first voltage of a first battery cell, a second voltage of a second battery cell, and a respective current that flows through the first and second battery cells. A first measured resistance of the first battery cell and a second measured resistance of the second battery cell is determined from the measured values. A reference resistance is determined. A first resistance relationship from the first measured resistance and the reference resistance and a second resistance relationship from the second measured resistance and the reference resistance are determined. A measured temperature of the first battery cell is determined. A computed temperature of the second battery cell is determined based on the measured temperature of the first battery cell, the first resistance relationship, and the second resistance relationship according to a predetermined requirement.