Traction Battery Impedance Spectroscopy Using Drive Power Electronics
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Solution Overview
Problem
Existing methods for analyzing the condition of a traction battery in motor vehicles require additional hardware, increasing manufacturing costs and weight, and often necessitate disconnecting the battery from the onboard power supply, rendering it unavailable for operation.
Innovation Solution
Utilize the power electronics of an electric or hybrid drive system to generate alternating current frequencies for impedance spectroscopy, eliminating the need for additional hardware and allowing analysis while the vehicle is in motion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If additional hardware (alternator) is added to perform impedance spectroscopy, then battery condition analysis capability is improved, but manufacturing cost and vehicle weight increase
Solution Approach 1:
The power electronics unit, originally designed solely for motor control, is made multi-functional by enabling it to also generate alternating current for impedance spectroscopy measurements. This allows the same hardware to serve dual purposes: operating the electric motor and analyzing battery condition, thereby eliminating the need for separate measurement hardware and reducing overall system complexity
Solution Approach 2:
The battery management system performs self-diagnosis by using its own power electronics unit to generate test signals for impedance spectroscopy. The system serves itself by utilizing existing components for both operation and monitoring, eliminating the need for external or additional dedicated measurement equipment
2Measurement precision
If battery is disconnected from onboard power supply for analysis, then measurement accuracy is improved, but vehicle operation capability is lost
Solution Approach 1:
The impedance spectroscopy measurements are performed continuously or periodically while the battery remains connected and the vehicle operates normally. The power electronics unit seamlessly generates measurement signals superimposed on the operational current, allowing simultaneous battery monitoring and vehicle operation without interruption
Solution Approach 2:
The system dynamically adapts by generating alternating current signals through the power electronics unit while the battery is under load during normal operation. This dynamic approach allows measurements to be taken in real-world operating conditions rather than requiring static, disconnected measurement scenarios
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
Enables a reliable and cost-effective analysis of traction battery parameters without additional hardware, reducing load on the battery and maintaining vehicle operation.
Implementation Method 1
performing impedance spectroscopy on the traction battery with one alternating current across multiple alternating current frequencies
Implementation Method 2
a frequency-dependent alternating current resistance of the battery is determined
Data Source
AI summary
A motor vehicle and method for analyzing the condition of a traction battery of a motor vehicle, wherein the motor vehicle includes an electric or hybrid propulsion system with an electric motor for driving the motor vehicle, power electronics for driving the electric motor, a battery management system with a monitoring device for monitoring the traction battery, and the traction battery. Impedance spectroscopy is performed on the traction battery with an alternating current across multiple alternating current frequencies. At least one battery parameter of the traction battery is determined based on the impedance spectroscopy performed. In the context of impedance spectroscopy, the traction battery is supplied with alternating current at several alternating current frequencies by the power electronics.