BMS Monitoring Control & Protection Algorithms 2

Question 1

Which algorithm technique is most commonly used to estimate battery State of Charge (SOC) when current sensor noise is significant?

Accepted Answer

Extended Kalman Filter (EKF)

Answer

The Extended Kalman Filter fuses voltage and current measurements with a battery model to suppress sensor noise and provide accurate SOC estimates.

Question 2

In a multi-cell BMS, what is the primary purpose of passive cell balancing?

Accepted Answer

Dissipating excess charge from higher-SOC cells as heat

Answer

Passive balancing bleeds energy from higher-capacity cells through resistors, equalizing SOC at the cost of wasted heat.

Question 3

A BMS detects a cell voltage below the under-voltage protection threshold. What is the correct immediate protection response?

Accepted Answer

Open the main contactor to disconnect the load

Answer

Under-voltage protection requires immediate load disconnection via the main contactor to prevent deep discharge damage.

Question 4

What does the term 'State of Health (SOH)' specifically quantify in a BMS?

Accepted Answer

Ratio of current maximum capacity to original rated capacity

Answer

SOH expresses capacity fade as the ratio of present usable capacity to the factory-rated capacity, typically expressed as a percentage.

Question 5

Which protection algorithm parameter defines the maximum allowable continuous discharge current for a lithium-ion pack?

Accepted Answer

Continuous Discharge Current (CDC)

Answer

The Continuous Discharge Current rating sets the sustained current ceiling beyond which overcurrent protection triggers.

(BMS) Battery Management System Certification Practice Test