Energy Storage Diagnostics Using Sub-Ignition Measurement Current
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Solution Overview
Problem
Existing vehicle safety systems rely on energy storage devices for airbag deployment and electronic drive disconnection during accidents, but there is a need to diagnose the state of charge and health status of these devices to ensure sufficient energy is available for proper functioning.
Innovation Solution
A device is coupled to a circuit arrangement with a controllable semiconductor switch and an ignition unit, where a control unit adjusts the current to a measurement current between 1% and 40% of the ignition current to determine the capacitance and internal impedance of the energy storage device, allowing for monitoring of the device's state.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the main battery is used to power the airbag system and electronic drive, then the energy capacity is sufficient, but the system becomes vulnerable to power loss during accidents
Solution Approach 1:
The system performs preliminary charging of the energy storage device (capacitor) during normal operation before an accident occurs. The control unit monitors the state of charge and ensures the capacitor is charged to a level sufficient to power the airbag system and electronic drive interruption during a crash event, eliminating the need for main battery power at the critical moment.
2Reliability
If a separate energy storage device is added for accident situations, then the reliability during crashes improves, but the device complexity increases
Solution Approach 1:
The energy storage device (capacitor) is designed to serve multiple functions: it powers the airbag system during deployment, provides energy for the electronic drive interruption system during accidents, and its state is monitored by the control unit for diagnostic purposes. This multi-functionality reduces the need for separate dedicated power sources for each safety system.
Solution Approach 2:
The control unit continuously monitors the state of charge and health status of the energy storage device using feedback from sensors. This feedback mechanism allows the system to diagnose the capacitor's condition, ensure sufficient energy is available for safety operations, and potentially alert the driver or service personnel if the energy storage device requires replacement.
3Ease of operation
If the ignition current is used directly for measurement, then the measurement is simple, but the ignition unit may be triggered unintentionally
Solution Approach 1:
The control unit adjusts the measurement current to a reduced level (between 1% and 40% of the ignition current threshold) during diagnostic operations. This parameter change allows the system to measure the electrical characteristics of the ignition unit and circuit without reaching the threshold that would trigger pyrotechnic ignition, thereby eliminating the harmful effect of unintentional activation.
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 solution enables effective monitoring of the energy storage device's capacitance and impedance, ensuring that it can provide the necessary energy for airbag deployment and electronic drive disconnection during accidents, thereby ensuring safety.
Implementation Method 1
the first semiconductor switch adjusts an electrical current through the first semiconductor switch and the ignition unit to a predefined current referred to as a measurement current
Implementation Method 2
an input of the sensor unit, referred to as a sensor input, is configured to be coupled to the circuit arrangement and to detect a voltage, referred to as a detection voltage, representing an electrical voltage of the energy storage device
Implementation Method 3
the control unit is configured to determine an electrical capacitance and/or an internal electrical impedance of the energy storage device based on the measured values
Implementation Method 4
the control unit is configured to determine an electrical capacitance and/or an internal electrical impedance of the energy storage device
Implementation Method 5
the ignition unit is configured to ignite upon reaching a predefined current flowing through the ignition units, referred to as an ignition current
Data Source
AI summary
The present invention relates to a device, which is configured to control a circuit arrangement, connected to an energy storage device, such that a predefined measurement current is caused to flow through the circuit arrangement and the energy storage device. The device may detect voltage values of the energy storage device at different times, while the measurement current is flowing, such that a healthy message of the energy storage device can be generated based on the detected voltages. The present invention also relates to a corresponding system and method.