EVT Thermal Management & Cooling Systems Flashcards
6 cards from real EVT practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 EVT Thermal Management & Cooling Systems flashcards as text
What is the primary purpose of the Battery Thermal Management System (BTMS) in an electric vehicle?
Answer: Maintain battery pack temperature within an optimal operating range to maximize life and performance
The BTMS keeps the battery cells within their optimal temperature window—typically 15–35 °C—to preserve capacity, cycle life, and safe operation.
A liquid-cooled battery pack uses ethylene glycol–water (EGW) coolant. What is the MAIN advantage of liquid cooling over air cooling for high-capacity packs?
Answer: Higher heat transfer coefficient enabling tighter temperature uniformity across cells
Liquid coolants have far higher thermal conductivity than air, allowing more efficient heat removal and tighter cell-to-cell temperature variation (typically <5 °C delta).
Which component in an EV thermal system transfers heat between the refrigerant circuit and the battery coolant loop without mixing the fluids?
Answer: Chiller (refrigerant-to-coolant heat exchanger)
The chiller is a refrigerant-to-coolant heat exchanger that cools the glycol-water battery coolant loop by evaporating refrigerant on the other side.
During a hot summer day, a technician notes the EV's available charge rate drops significantly. What is the most likely cause?
Answer: Battery thermal management system limiting charge rate to prevent overheating
High ambient temperatures cause the BTMS to throttle charge current to keep cell temperatures within safe limits, resulting in reduced charge acceptance.
What does a negative temperature coefficient (NTC) thermistor do as its temperature increases?
Answer: Its resistance decreases
An NTC thermistor decreases in resistance as temperature rises, and this predictable change is used by the BMS to calculate battery pack temperature.
A technician replaces coolant in a liquid-cooled battery pack. What is a critical step BEFORE refilling?
Answer: Flush the system with distilled water and verify no contamination or air pockets remain
Flushing ensures old degraded coolant and any debris are removed, and purging air prevents hot spots from air pockets that reduce heat transfer.