Handling a fault condition on a lithium-battery-powered utility vehicle

A utility vehicle, comprising:

• a utility vehicle body;
• an electric motor supported by the utility vehicle body;
• and
• a control system coupled with the motor, the control system including:
• a lithium battery,
• a battery contactor configured to control electrical access to the lithium battery, and
• control circuitry coupled with the lithium battery and the battery contactor, the control circuitry being configured to:
• while the battery contactor is closed to provide the motor with electrical access to the lithium battery, detect onset of a fault condition,
• in response to detection of the onset of the fault condition, perform a set of remedial operations to address the fault condition, and
• after a predefined amount of time has elapsed since the onset of the fault condition, perform a subsequent operation which (i) opens the battery contactor if the fault condition remains and (ii) maintains closure of the battery contactor if the fault condition does not remain;
• wherein the control circuitry is constructed and arranged to energize an electric brake to allow the utility vehicle to move while detecting onset of the fault condition;
• wherein the control circuitry, when performing the set of remedial operations to address the fault condition, is constructed and arranged to:
• de-energize, as one of the set of remedial operations, the electric brake to stop rotation of the electric motor prior to opening the battery contactor to prevent the utility vehicle from stopping abruptly;
• and
• wherein opening the battery contactor disconnects the electric motor from access to electric power.

In a lithium-battery powered utility vehicle, a method of handling a fault condition, the method comprising:

• while a battery contactor is closed to provide an electric motor of the lithium-battery powered utility vehicle with electrical access to the lithium battery, detecting onset of a fault condition,
• in response to detection of the onset of the fault condition, performing a set of remedial operations to address the fault condition, and
• after a predefined amount of time has elapsed since the onset of the fault condition, performing a subsequent operation which (i) opens the battery contactor if the fault condition remains and (ii) maintains closure of the battery contactor if the fault condition does not remain;
• wherein control circuitry of the lithium battery powered utility vehicle is constructed and arranged to energize an electric brake to allow the vehicle to move while detecting onset of the fault condition;
• wherein performing the set of remedial operations to address the fault condition includes:
• de-energizing, by the control circuitry and as one of the set of remedial operations, the electric brake to stop rotation of the electric motor of the lithium battery powered utility vehicle prior to opening the battery contactor to prevent the lithium battery powered utility vehicle from stopping abruptly;
• and
• wherein opening the battery contactor disconnects the electric motor from access to electric power.