Control device and control method for electric vehicle

A control device for an electric vehicle, comprising:

• a current sensor adapted to detect a charge/discharge current of a battery of the vehicle;
• a voltage sensor adapted to detect an open circuit voltage of the battery;
• a battery controller adapted to detect a residual capacity of the battery based on the charge/discharge current detected by the current sensor and the open circuit voltage detected by the voltage sensor;
• a vehicle controller configured to control an electric load arranged to operate with electric power supplied from the battery;
• and
• a meter, wherein
• the battery controller is programmed to:
• calculate a first residual capacity based on an integrated value of the charge/discharge current of the battery detected by the current sensor;
• calculate a second residual capacity based on the open circuit voltage of the battery detected by the voltage sensor;
• determine a blend rate of the second residual capacity based on a deviation between the first residual capacity and the second residual capacity;
• calculate a post-combination residual capacity by subjecting the first residual capacity and the second residual capacity to weighted combination with use of the blend rate;
• increase the blend rate as the first residual capacity increases relative to the second residual capacity during discharging or as the second residual capacity increases relative to the first residual capacity during charging;
• and
• use the calculated post-combination residual capacity as a detection value of the residual capacity of the battery to reduce an estimation error of the residual capacity of the battery due to a cell abnormality, and
• the vehicle controller is further configured to, when it is determined that the post-combination residual capacity is insufficient, limit the electric power consumption of the electric load and cause the meter to display the post-combination residual capacity to a driver.