Battery Temperature Measurement Circuit With Auto-Ranging Current
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Solution Overview
Problem
Existing battery management systems for electric vehicles face challenges in accurately and efficiently measuring battery cell temperatures, particularly due to the non-linearity of temperature-sensitive resistors and long settling times, which can impact safety and operational efficiency.
Innovation Solution
The implementation of a temperature measurement circuit that determines an auto-ranging current through a temperature-sensitive resistor using a pre-defined reference voltage, allowing for the definition of a temperature measurement current, which is then used to measure the temperature-dependent voltage drop, thereby improving measurement accuracy and reducing settling time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a temperature-sensitive resistor is used to measure battery cell temperature, then temperature monitoring capability is provided, but measurement accuracy deteriorates due to non-linearity of the resistor
Solution Approach 1:
The patent applies preliminary action by performing an auto-ranging current measurement step before the actual temperature measurement. This preliminary step determines the appropriate current range based on the temperature-sensitive resistor's characteristics, allowing the system to compensate for non-linearity and improve measurement accuracy while maintaining reliable temperature monitoring capability
Solution Approach 2:
The patent changes the measurement parameter by using auto-ranging current instead of fixed current through the temperature-sensitive resistor. By dynamically adjusting the current range based on preliminary measurements, the system compensates for the resistor's non-linear behavior across different temperature ranges, thereby improving measurement precision while maintaining monitoring reliability
2Reliability
If conventional temperature measurement methods are used, then temperature monitoring is achieved, but settling time increases affecting operational efficiency
Solution Approach 1:
The patent performs preliminary auto-ranging current measurement to determine the optimal measurement parameters before conducting the actual temperature measurement. This preliminary action enables the system to quickly converge to the correct measurement range, significantly reducing settling time while maintaining reliable temperature monitoring
Solution Approach 2:
The patent introduces dynamic current ranging that adapts based on preliminary measurements. Instead of using a fixed measurement approach, the system dynamically adjusts the current range to match the actual temperature conditions, enabling faster settling and more efficient operation while maintaining monitoring reliability
3Measurement precision
If external reference devices are used for temperature measurement, then measurement reference accuracy is provided, but device complexity increases
Solution Approach 1:
The patent implements self-service by using the temperature-sensitive resistor itself to generate the reference information needed for measurement. Through auto-ranging current measurement, the system extracts reference data from the resistor's own characteristics, eliminating the need for separate external reference devices and reducing overall circuit complexity while maintaining measurement precision
Solution Approach 2:
The patent merges the reference function with the temperature-sensitive resistor by using the same component for both temperature sensing and reference generation. This consolidation eliminates external reference devices, simplifies the circuit architecture, and maintains accurate temperature measurement through the integrated approach
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 enables faster and more accurate temperature measurements, reducing the settling time and eliminating the need for additional external reference devices, thus enhancing the operational safety and efficiency of battery management systems.
Implementation Method 1
measuring a temperature-dependent voltage drop over a temperature sensitive resistor
Data Source
AI summary
In some examples, this disclosure describes a method of measuring a temperature-dependent voltage drop over a temperature sensitive resistor. The method may comprise delivering a reference voltage to the temperature sensitive resistor in a first instance of time; determining an auto-ranging current through the temperature sensitive resistor while the reference voltage is delivered to the temperature sensitive resistor; determining a temperature measurement current based on the auto-ranging current; delivering the temperature measurement current to the temperature sensitive resistor in a second instance of time, wherein the second instance of time is after the first instance of time; and measuring the temperature-dependent voltage drop over the temperature sensitive resistor while the temperature measurement current is delivered to the temperature sensitive resistor.