EV Battery Support Determination Using Voltage and Internal Resistance
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Solution Overview
Problem
Current battery management systems for electric vehicles fail to meet ASIL B safety standards due to difficulties in generating reliable results for battery energy content and power support, as existing methods rely on complex cell models that are impractical for high-reliability measurements.
Innovation Solution
A method and detection system that determine battery energy content and power support by measuring battery voltage and internal resistance against threshold values, using simple mathematical operations and logical operators, ensuring ASIL B quality through accurate input verification, and accounting for temperature-dependent resistances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex cell models are used to determine battery energy content and power support, then measurement precision may be improved, but device complexity and reliability deteriorate due to practical implementation difficulties and error propagation
Solution Approach 1:
The patent extracts only the essential parameters (voltage, current, temperature) needed for battery state determination from the complex cell model, eliminating unnecessary model complexity while retaining measurement accuracy. This is achieved by directly measuring terminal voltage and current, and using temperature compensation tables rather than complex electrochemical models.
Solution Approach 2:
The patent replaces complex, error-prone cell models with simple, robust measurement equations that are computationally inexpensive and highly reliable. The approach uses basic electrical measurements (voltage, current) combined with temperature compensation rather than sophisticated modeling, achieving ASIL B reliability through simplicity.
2Loss of information
If complex cell models are used for battery determination, then potentially more detailed information can be obtained, but reliability deteriorates due to errors in complex calculations
Solution Approach 1:
The patent implements temperature compensation through lookup tables that provide correction factors based on measured temperature. This feedback mechanism adjusts the capacity and power values based on actual temperature conditions, ensuring reliable determination across different operating temperatures without using complex models.
Solution Approach 2:
The patent changes the approach from using complex dynamic models to using static measurement equations with temperature-dependent correction factors. The capacity and power are determined using straightforward calculations based on voltage, current, and temperature-compensated values, eliminating calculation errors while maintaining information completeness.
3Device complexity
If simple measurement methods are used, then device complexity is reduced, but measurement precision deteriorates due to insufficient accounting for temperature effects
Solution Approach 1:
The patent accounts for temperature effects by changing the capacity and power parameters based on measured temperature and predefined compensation factors. The terminal voltage, current, and temperature measurements are combined with temperature-dependent correction tables to determine accurate capacity and power values, maintaining precision through simple parameter adjustments rather than complex modeling.
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 reliable verification of battery energy and power support, meeting ASIL B standards by simplifying the measurement process and avoiding errors associated with complex cell models, ensuring safe and efficient operation of electric vehicles.
Implementation Method 1
measuring a terminal voltage and a current of the battery
Implementation Method 2
determining an internal resistance of the battery
Data Source
Figure 1~2
Figure 3
AI summary
The present invention refers to a method and a detection system (1) for determining the support of an energy content and a power of a battery for an electric vehicle, wherein determining the support of the energy content comprises: measuring a voltage (Usys) of the battery, comparing the measured voltage (Usys) with a predetermined threshold voltage (Ulim) and determining if the measured voltage (Usys) is equal or larger than the predetermined threshold voltage (Ulim). Further, determining the support of the power comprises determining an internal resistance (Rsys) of the battery, comparing the determined internal resistance (Rsys) with a predetermined threshold resistance (Rlim) and determining if the determined internal resistance (Rsys) is equal or less than the predetermined threshold resistance (Rlim). Further, the method comprises determining that the energy content and the power of a battery of an electric vehicle is supported, if both the measured voltage (Usys) is equal or larger than the predetermined threshold voltage and the determined resistance (Rsys) is equal or less than the predetermined threshold resistance (Rlim).