ASE Light Duty Hybrid/Electric Vehicle 3 — Questions and Answers
Question 1: What battery chemistry is most commonly used in modern light-duty plug-in electric vehicles?
- Lithium-ion (Correct answer)
- Lead-acid
- Nickel-cadmium
- Alkaline
Correct answer: Lithium-ion
Lithium-ion batteries offer high energy density and are standard in current EVs and most plug-in hybrids.
Question 2: What is the function of regenerative braking in a hybrid/electric vehicle?
- It converts kinetic energy into electricity to recharge the battery (Correct answer)
- It increases engine compression
- It cools the brake calipers with refrigerant
- It locks the wheels faster
Correct answer: It converts kinetic energy into electricity to recharge the battery
Regenerative braking uses the motor as a generator to recover energy that would otherwise be lost as heat.
Question 3: A customer reports reduced fuel economy and frequent engine starts in their hybrid. Which is a likely cause?
- A degraded high-voltage battery with reduced capacity (Correct answer)
- An overinflated spare tire
- A dirty cabin air filter
- A loose license plate
Correct answer: A degraded high-voltage battery with reduced capacity
As the HV battery loses capacity, the engine runs more often to maintain charge, lowering efficiency.
Question 4: What is the role of the inverter in an electric drive system?
- It converts DC from the battery to AC for the traction motor (Correct answer)
- It filters the engine oil
- It charges the 12V battery from the alternator
- It controls the transmission fluid pressure
Correct answer: It converts DC from the battery to AC for the traction motor
The inverter changes high-voltage DC battery power into three-phase AC needed to run the traction motor.
Question 5: What is the purpose of the DC-DC converter on a hybrid/electric vehicle?
- It steps down high voltage to charge the 12V system (Correct answer)
- It increases battery voltage to 800V
- It converts AC to DC for the motor
- It heats the catalytic converter
Correct answer: It steps down high voltage to charge the 12V system
The DC-DC converter replaces the alternator by stepping high voltage down to power the 12V accessories and battery.
Question 6: Which cooling method is commonly used for high-voltage battery packs to maintain optimal temperature?
- Liquid or active air thermal management (Correct answer)
- Engine exhaust heat
- Transmission fluid only
- No cooling is ever needed
Correct answer: Liquid or active air thermal management
Battery packs use liquid or forced-air thermal management to keep cells within their safe operating temperature range.
Question 7: What should a technician do with a high-voltage battery pack that shows signs of thermal runaway or swelling?
- Isolate it, follow OEM emergency procedures, and avoid direct contact (Correct answer)
- Continue normal service immediately
- Puncture it to release pressure
- Place it near a heat source
Correct answer: Isolate it, follow OEM emergency procedures, and avoid direct contact
A compromised lithium battery is a fire and chemical hazard, so it must be isolated and handled per manufacturer safety protocols.
ASE Light Duty Hybrid/Electric Vehicle 3
What battery chemistry is most commonly used in modern light-duty plug-in electric vehicles?