Vehicle Battery Energy Estimation from Ripple Current for Emergency Pulses
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Solution Overview
Problem
Modern vehicles lack effective methods to diagnose a defective vehicle battery before starting, especially when the starting operation is not assisted by a pinion start, posing a risk to safety-relevant systems during emergencies.
Innovation Solution
A method using a battery monitoring device to determine the internal resistance value from ripple current, combined with temperature and discharge current, to predict the available energy for an emergency pulse, generating a warning signal if the energy falls below a preset threshold, and adjusting vehicle operations accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pinion start is used for starting operation, then battery diagnosis can be performed by high starting current, but modern vehicles without pinion start cannot diagnose defective vehicle battery
Solution Approach 1:
The patent replaces the mechanical pinion start system with an electrical starting system (starter motor), and consequently replaces the mechanical-based diagnosis method (high starting current test) with an electrical measurement method (ripple current analysis). The control unit measures ripple currents in the electrical starting circuit to determine battery health, eliminating the need for mechanical pinion engagement while maintaining diagnostic capability.
Solution Approach 2:
The patent changes the diagnostic parameter from high starting current (mechanical system) to ripple current characteristics (electrical system). By analyzing the amplitude and frequency of ripple currents during normal electrical starting operation, the system can assess battery internal resistance and state of charge without requiring the extreme current conditions of pinion starting, thus adapting to modern starting systems while maintaining diagnostic reliability.
2Reliability
If classical high starting current diagnosis is used, then defective battery can be detected before start, but this method does not provide continuous monitoring during vehicle operation
Solution Approach 1:
The patent implements continuous monitoring of battery health by measuring ripple currents during normal vehicle operation, rather than performing a single pre-start diagnosis. The control unit continuously analyzes ripple current characteristics, enabling ongoing assessment of battery internal resistance and state of charge throughout the vehicle's operational life, thus extending monitoring duration from a single point in time to continuous operation.
Solution Approach 2:
The system establishes a feedback loop where the control unit continuously measures ripple currents, processes the signals to determine battery parameters, and uses this information to assess battery health in real-time. This feedback mechanism enables the system to detect degradation trends and provide continuous reliability assessment rather than a one-time check.
3Reliability
If ripple current measurement is used to determine internal resistance, then continuous monitoring is enabled, but additional measurement infrastructure is required
Solution Approach 1:
The patent makes the existing current measurement infrastructure serve multiple functions: it measures both the starting current for vehicle operation and the ripple current for battery diagnosis. The same sensors and control unit used for normal vehicle control are utilized to extract ripple current signals, eliminating the need for separate dedicated measurement devices and reducing overall system complexity despite enabling continuous monitoring.
Solution Approach 2:
The system uses the vehicle's own operational current signals (ripple currents during normal operation) as the diagnostic test signal, rather than requiring external test equipment or separate measurement systems. The battery's normal operational characteristics provide the measurement data needed for self-diagnosis, allowing the system to monitor its own health using existing infrastructure.
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 continuous monitoring and timely warning of insufficient battery energy, ensuring safety by enabling emergency operations and optimizing energy usage, thereby enhancing vehicle safety and efficiency.
Implementation Method 1
determining an internal resistance value of the vehicle battery from a measured ripple current. A superimposed alternating current or zero-mean alternating portions of a battery current and/or a battery voltage are meant by ripple current
Data Source
AI summary
An internal resistance value of a vehicle battery is determined from a measured ripple current. An actual energy content of the vehicle battery is determined from the internal resistance value and a predetermined battery characteristic curve. A temperature value of the vehicle battery is measured and an available amount of energy of the vehicle battery for an emergency pulse is determined based on the actual energy content, an actual discharge current of the vehicle battery and the measured temperature value.