CAR Electric & Hybrid Vehicle Processing 3 — Questions and Answers
Question 1: A recycler is processing a flood-damaged Tesla Model 3. Which action should be taken FIRST before any other disassembly step?
- Isolate the 12V auxiliary battery to disable the high-voltage contactor circuit (Correct answer)
- Remove the charge port to prevent accidental charging
- Check the touchscreen for fault codes
- Drain the coolant from the battery thermal management system
Correct answer: Isolate the 12V auxiliary battery to disable the high-voltage contactor circuit
Disconnecting the 12V auxiliary battery opens the BMS control circuit, preventing the high-voltage contactors from closing and energizing the drive system.
Question 2: Under EPA regulations, a used EV high-voltage battery pack that tests above 80% capacity and is resold for second-life energy storage is classified as:
- A reuse product, not a solid waste (Correct answer)
- A Universal Waste
- A hazardous waste requiring a manifest
- A regulated recyclable material
Correct answer: A reuse product, not a solid waste
EPA's solid waste definition excludes materials that are legitimately reused as products; a battery sold into second-life storage avoids solid waste classification.
Question 3: What is the function of the pyrotechnic safety switch (PSS) found in some EV battery packs such as those in BMW i3 vehicles?
- It permanently severs the high-voltage circuit upon deployment of airbags (Correct answer)
- It vents gases from individual cells during thermal runaway
- It disconnects the 12V auxiliary battery in a crash
- It triggers automatic cooling fluid circulation after impact
Correct answer: It permanently severs the high-voltage circuit upon deployment of airbags
The PSS uses a small explosive charge to physically cut the high-voltage bus bar, permanently isolating the battery when the airbag control module detects a severe crash.
Question 4: When testing a recovered EV battery pack for second-life potential, which parameter is the most critical indicator of remaining usable capacity?
- State of health (SOH) measured via capacity test (Correct answer)
- Open-circuit voltage (OCV) only
- Internal temperature at rest
- Cell balancing voltage spread at 100% SOC
Correct answer: State of health (SOH) measured via capacity test
SOH—expressed as a percentage of original rated capacity—is the definitive measure of battery degradation and determines suitability for second-life applications.
Question 5: A recycling facility worker notices a stored EV battery emitting a sweet or chemical odor and feels warm to the touch. The correct immediate response is to:
- Move it to an outdoor fire containment area and notify the fire department (Correct answer)
- Pour water directly on the pack to cool it down
- Place it in a sealed metal drum to contain gases
- Attach a charge cable to stabilize the cells
Correct answer: Move it to an outdoor fire containment area and notify the fire department
Odd odors and heat are early thermal runaway indicators; the pack must be moved outside immediately and emergency services alerted before full runaway occurs.
Question 6: Which high-voltage component in a hybrid vehicle stores energy recovered during regenerative braking in a Honda Accord Hybrid?
- A nickel-metal hydride battery module (Correct answer)
- A lithium-iron-phosphate ultracapacitor
- A lead-acid buffer battery
- A flywheel energy recovery unit
Correct answer: A nickel-metal hydride battery module
Honda's IMA and later hybrid systems use nickel-metal hydride battery modules to capture and store kinetic energy converted to electricity during braking.
Question 7: During EV battery pack disassembly, technicians must use insulated tools rated for at least how many volts to safely work near exposed busbars?
- 1,000 V (Correct answer)
- 500 V
- 600 V
- 300 V
Correct answer: 1,000 V
NFPA 70E and OEM service standards require insulated hand tools rated at minimum 1,000 V for work on or near live or potentially live high-voltage automotive systems.
CAR Electric & Hybrid Vehicle Processing 3
A recycler is processing a flood-damaged Tesla Model 3.
Which action should be taken FIRST before any other disassembly step?