Battery Technology & Energy Storage Flashcards
7 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 7 Battery Technology & Energy Storage flashcards as text
What is the primary cause of lithium plating in a lithium-ion battery cell?
Answer: Charging at rates exceeding the anode's lithium insertion capacity
Lithium plating occurs when the charging rate exceeds the anode's ability to intercalate lithium ions, causing metallic lithium to deposit on the anode surface.
A battery management system (BMS) detects a single cell with a voltage of 2.8V while all other cells in the pack read 3.7V. What is the most likely diagnosis?
Answer: Severely degraded or defective cell requiring pack inspection
A cell reading 2.8V while others read 3.7V indicates the cell is deeply discharged or failing, and the pack must be inspected to determine if the cell needs replacement.
Which electrolyte property is most critical for preventing thermal runaway propagation between cells?
Answer: Low vapor pressure and high flash point
A low vapor pressure and high flash point electrolyte reduces the risk of ignition and slows thermal runaway propagation by limiting flammable vapor generation.
What does the term 'C-rate' describe in battery technology?
Answer: The charge or discharge current relative to the battery's capacity
C-rate expresses current as a multiple of battery capacity; a 1C rate fully charges or discharges a battery in one hour.
In a nickel-metal hydride (NiMH) battery used in hybrid vehicles, what is the primary advantage over early lead-acid designs?
Answer: Greater specific energy and better cycle life
NiMH batteries offer significantly higher specific energy and longer cycle life than lead-acid batteries, making them suitable for hybrid vehicle applications.
Which condition will most rapidly accelerate capacity fade in a lithium-ion EV battery?
Answer: Repeatedly charging to 100% and discharging to 0% at high temperatures
Repeated full charge/discharge cycles at elevated temperatures cause severe electrolyte decomposition, SEI layer growth, and active material degradation, rapidly accelerating capacity fade.
What is the function of the solid electrolyte interphase (SEI) layer on a lithium-ion anode?
Answer: It acts as a protective passivation layer that prevents further electrolyte decomposition
The SEI layer forms during initial cycling and acts as a passivation film that prevents further electrolyte reduction while still allowing lithium ion transport.