Relay Control System for EV Battery Fusion Detection
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Solution Overview
Problem
In electric vehicles, the lack of shared request signals among controllers for turning off the main relay can lead to a fused relay, causing overcharge or over-discharge of the battery, which may result in explosion or electric shock due to the battery management system's inability to manage the state of charge effectively.
Innovation Solution
A relay control system that includes pre-charge units with relays and resistors connected in parallel to the main relays, using an operational amplifier to determine if the main relays are fused by measuring voltage values after a pre-charge period, allowing for safe pre-charging and preventing arc discharge or inrush current issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the main relay is turned off by one controller without sharing the request signal with other controllers, then the battery management system can protect the main battery, but the relay may be fused due to current supply from other controllers operating independently
Solution Approach 1:
The patent applies preliminary action by introducing a pre-charge relay that operates before the main relay. This pre-charge relay performs an initial connection and voltage measurement to detect relay fusion status before the main relay is activated. By executing this preliminary detection action, the system identifies potential relay fusion issues before they can cause harmful effects during main relay operation.
Solution Approach 2:
The patent uses an operational amplifier as an intermediary device to measure the voltage across the pre-charge relay terminals. This intermediary measurement mechanism provides indirect detection of relay fusion status without directly interfering with the main relay control logic. The voltage measurement serves as a mediator that translates the physical state of the relay into detectable electrical signals for the control system.
2Adaptability or versatility
If controllers do not share request signals for turning off the main relay, then each controller can independently manage battery protection, but the lack of coordination causes relay fusion and battery management failure
Solution Approach 1:
The patent implements self-service by enabling each controller to independently detect relay fusion status through the pre-charge relay voltage measurement mechanism. Instead of requiring inter-controller communication for coordination, each controller can autonomously determine whether the relay is fused by measuring the voltage across the pre-charge relay terminals, allowing independent decision-making while maintaining system reliability.
Solution Approach 2:
The patent establishes a feedback mechanism where the voltage measurement across the pre-charge relay terminals provides real-time information about relay fusion status back to the control system. This feedback loop allows controllers to adjust their operation based on the detected relay condition, ensuring that no controller attempts to operate a fused relay, thereby maintaining battery management stability despite independent operation.
3Productivity
If the main relay is turned on without pre-charge, then the battery can immediately supply power to loads, but inrush current and arc discharge may damage the relay
Solution Approach 1:
The patent applies preliminary action by introducing a pre-charge phase before the main relay operation. The pre-charge relay is activated first to establish an initial connection, allowing the circuit to charge capacitive loads and establish a stable voltage condition. This preliminary action prepares the circuit for subsequent main relay operation, preventing harmful inrush currents and arc discharge by ensuring the circuit is already charged when the main relay closes.
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 early detection of fused relays before the main relays are turned on, improving the stability of the battery management system by preventing overcharge or over-discharge, thus ensuring safety and efficient battery management.
Implementation Method 1
an operational amplifier having both terminals connected to the first and second nodes and outputting a voltage applied to the load to an output terminal
Data Source
AI summary
The present invention relates to a relay control system and a control method thereof, and more particularly, to a relay control system and a control method thereof capable of determining whether an unrecoverable failure of a relay due to an unexpected environment, namely, whether the relay is fused, by measuring a voltage on a relay in real time while a battery unit operates in a secondary cell battery using DC power.