Battery Pack Relay Voltage Control for Switch Withstand Limits
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Solution Overview
Problem
Existing relay control systems for battery packs are unable to prevent damage from overvoltage, as they do not set the reference voltage based on the withstanding voltage of the charging and discharging switches, leading to potential damage even without overcurrent conditions.
Innovation Solution
A relay control apparatus that includes a comparator to set the operation state of a relay based on a reference voltage corresponding to the withstanding voltage of the relay, using a diode to direct current flow and a controller to adjust the reference voltage via a variable resistor, ensuring the relay operates within safe voltage limits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the reference voltage is set based on the maximum voltage of the capacitor, then high current can be prevented, but the charging switch and discharging switch may be damaged by voltage exceeding their withstanding voltage
Solution Approach 1:
The patent changes the reference voltage parameter from being based on capacitor maximum voltage to being based on the minimum withstanding voltage of the charging and discharging switches. This parameter change ensures that the reference voltage reflects the actual voltage tolerance limits of the switching components, preventing voltage-induced damage while maintaining overcurrent protection functionality.
2Extent of automation
If the BMS controls the operation state of charging and discharging switches, then battery management is achieved, but control is impossible when the BMS is in wake-up state
Solution Approach 1:
The patent implements preliminary protection action by setting the reference voltage based on switch withstanding voltage before any charging or discharging operation occurs. This preliminary configuration ensures that even when the BMS is in wake-up state and cannot actively control the switches, the voltage reference is already properly configured to prevent damage, providing fail-safe protection independent of BMS operational state.
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
Prevents surges from flowing into the relay, thereby preventing damage and ensuring the battery pack's components are protected from voltage-related issues, even as the relay degrades or is replaced.
Implementation Method 1
The relay may include a diode disposed so that a direction from the battery cell toward the pack terminal is a forward direction
Implementation Method 2
a comparator configured to receive a comparison voltage from the main path and output a result signal to the relay based on a difference between a reference voltage and the comparison voltage
Data Source
AI summary
A relay control apparatus according to an embodiment of the present disclosure includes: a relay disposed on a main path between a battery cell and a pack terminal and for electrically connecting or disconnecting the main path according to an operation state of the relay; and a comparator for receiving a comparison voltage from the main path and outputting a result signal to the relay based on a difference between a reference voltage and the comparison voltage, the relay is receives the result signal and controls the operation state of the relay to a turn-on state or a turn-off state according to the magnitude of the received result signal.