Week 7 State of charge estimation

# Question no:1

# Case1:

• 

- The vehicle is initially in driving state and charging wa done till 90%. After charging it reaches to standby mode. It can be seen in BMS plot.

- Battery temperature increases in driving and charging. Battery voltage was increased to 4.2 V while charging.

- Current plot shows value of current supplied to vehicle while driving. SOC decresed up to 50% in driving condition and it was increased while charging.

# Case:2

From graph, a fault condition occured in second case. So even after charging was started, SOC didnt increase.

# Case:3

- SOC reached 100% in charging and remained in standstill by mode. Cell tempreture aso decreased as in standby mode oprated.

# Question no:2

- Coulomb counting:

Coulomb counting method measures the discharging current of a battery and integrates the discharging current over time in order to esrimate SOC.

Coulomb counting method is done to estimate the, which is estimated from the discharging current, and previously estimated SOC values.

SOC is calculated using following formula:

• BMS implementation:

• Subsystem of BMS ECU:

• SOC estimation block:

-After clicking on coulomb counting:

This method does the estimation by coulomb counting equation mentioned above.

- Temperature and current from battery is given as inputs.

- Current signal is given to gain block and teperature is given to capacity since it varies according to temperature.

- These inputs are integrated with respect to time.

- This output is given to another block where it s divided by capacity.hence SOC is estimated.