Utility Vehicle Brake Release Control for Lithium BMS Protection
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Solution Overview
Problem
Conventional methods for releasing electromagnetic parking brakes in electric vehicles equipped with lithium batteries are inefficient, leading to over-discharge and instability due to the lack of automatic disconnection when the vehicle is not in motion.
Innovation Solution
A control system that electronically manages a lithium battery management system (BMS) to close and open a contactor in response to a tow signal and vehicle motion, ensuring power is only provided to the electric brake when the vehicle is in use, thereby preventing over-discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the parking brake release lever is moved to the released position to provide power from the lithium battery to the electromagnetic parking brake, then the parking brake is released and the vehicle can be towed, but the battery continues to discharge and may become over-discharged leading to instability
Solution Approach 1:
The control system continuously monitors vehicle motion status and provides feedback to the battery management system. When motion is detected, the system maintains power supply to the brake release mechanism. When no motion is detected for a predefined period, the system automatically terminates power supply to prevent over-discharge, thus maintaining battery stability while enabling easy brake release operation.
Solution Approach 2:
The system automatically manages the power supply cycle without requiring manual intervention. The brake release mechanism self-activates when towing conditions are detected and self-deactivates after the predefined time period expires, enabling ease of operation while preventing battery over-discharge through automated control.
2Productivity
If power is continuously provided to the electromagnetic parking brake to ensure it remains released for towing, then the vehicle can be towed without impediment, but the lithium battery becomes unstable due to over-discharge
Solution Approach 1:
The system implements periodic monitoring of vehicle motion status during the towing process. Power is supplied to the brake release mechanism in periodic intervals - activated when motion is detected and deactivated after a predefined time period without motion. This periodic action ensures towing capability is maintained when needed while preventing continuous discharge that would destabilize the battery.
3Duration of action of moving object
If the brake release switch remains in the brake release position for an extended period, then the parking brake stays released allowing vehicle movement, but the lithium battery continues to discharge and becomes unstable
Solution Approach 1:
The system is pre-configured with a predefined time period threshold that automatically triggers power termination. This preliminary action is built into the control logic, so when the brake release switch is activated, the system automatically terminates power supply after the predefined time period expires, preventing extended discharge that would destabilize the battery while allowing sufficient duration for legitimate towing operations.
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 reliably prevents lithium battery over-discharge by automatically disconnecting power to the electric brake when the vehicle is stationary, safeguarding the battery against instability and ensuring efficient energy use.
Implementation Method 1
an electric brake configured to (i) provide mechanical resistance which inhibits a motor of the utility vehicle from turning when the electric brake is unpowered and (ii) remove the mechanical resistance to allow the motor of the utility vehicle to turn when power is provided to the electric brake
Implementation Method 2
a lithium battery management system (BMS) having a contactor configured to close to provide electrical access to a lithium battery and open to remove electrical access to the lithium battery
Data Source
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AI summary
A motion control system controls movement of a utility vehicle. The motion control system includes an electric brake that (i) provides mechanical resistance which inhibits a motor of the utility vehicle from turning when the electric brake is unpowered and (ii) removes the mechanical resistance to allow the motor of the utility vehicle to turn when power is provided to the electric brake. The motion control system further includes a lithium BMS having a contactor that closes to provide electrical access to a lithium battery and opens to remove electrical access to the lithium battery. The motion control system further includes control circuitry coupled with the electric brake and the lithium BMS. The control circuitry directs the lithium BMS to maintain closure of the contactor to provide power from the lithium battery to the electric brake in response to receipt of a tow signal.