Battery Protection Circuit Using Capacitor-Driven Latching Switch
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Solution Overview
Problem
Existing battery protection systems for vehicle engines face challenges in preventing damage from under-voltage, over-current, and over-discharge conditions, particularly due to the complexity of external switches and ongoing power consumption issues in normally closed contactor systems.
Innovation Solution
A current protection circuit incorporating a latching circuit and a capacitor-driven contactor circuit that automatically switches to an open configuration when voltage drops or current exceeds thresholds, disconnecting the battery to prevent damage, without the need for an external switch and minimizing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a normally opened contactor is used in the battery power circuit, then the battery is protected from excessive current or excessive depth of discharge, but the complexity of the vehicle design and operation increases due to the necessity of installing and operating an external switch
Solution Approach 1:
The battery protection system performs self-service by automatically detecting excessive current or depth of discharge conditions and actuating the contactor through its own internal circuitry. The battery's own voltage and current are used to trigger the protection mechanism, eliminating the need for external switches or manual intervention, thus reducing vehicle design complexity while maintaining reliable battery protection
2Device complexity
If a normally closed contactor is used in the battery power circuit, then no external switch is required to perform an engine start profile, but ongoing power consumption is required to energize the coil and keep the contactor open, which may completely drain the battery cells of energy and damage the battery
Solution Approach 1:
The system inverts the traditional approach by using a normally closed contactor that automatically opens under excessive current or depth of discharge conditions through its own internal circuitry, rather than requiring continuous power to remain open. The protection mechanism activates only when needed, eliminating ongoing power consumption while maintaining simple switching operation for engine start profiles
3Reliability
If the contactor is opened to protect the battery from excessive current or excessive depth of discharge, then the battery is protected from damage, but power is required to energize the coil which may completely drain the battery cells of energy
Solution Approach 1:
The protection system employs periodic action by only energizing the contactor coil when excessive current or depth of discharge conditions are detected. The system monitors battery parameters continuously and activates protection only during abnormal conditions, rather than maintaining continuous power consumption, thus protecting the battery from damage without causing excessive energy drain
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
The solution effectively protects batteries from excessive current and depth of discharge while enabling engine start profiles without external switches, reducing the risk of damage and power drain.
Implementation Method 1
a capacitor electrically coupled to the first circuit region. In some embodiments, the capacitor is configured to store power collected from the first circuit region and the microcontroller is configured to monitor a current or a voltage from the energy storage device and, if the current is above a current threshold value or the voltage is below a voltage threshold value, cause the capacitor to discharge to the operational switch of the latching circuit
Data Source
AI summary
A protection circuit for protecting an energy storage device includes a first circuit region between a first terminal of the energy storage device and a first connector node, a second circuit region between a second terminal of the energy storage device and a second connector node, a latching circuit to electrically couple the first connector node to the first terminal of the energy storage device when the latching circuit is in a closed configuration, and a contactor circuit electrically coupled to an operational switch of the latching circuit, the contactor circuit comprising a capacitor to store charge and a microcontroller to monitor an electrical property of the energy storage device to determine if a short circuit occurs and, if a short circuit does occur, cause the capacitor to discharge to the operational switch of the latching circuit to cause the latching circuit to transition to the open configuration.