Control device and control method for electric vehicle

• US 10,310,025 B2
• Filed: 03/08/2013
• Issued: 06/04/2019
• Est. Priority Date: 03/13/2012
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Soga, Tsutomu, Takano, Atsushi
• Primary Examiner(s): Satanovsky, Alexander
• Assistant Examiner(s): Fairbanks, Brent A.
• Application Number:
  US14/384,438
• Publication Number:
  US 20150134282A1
• Time in Patent Office: 2,279 Days
• Field of Search: None
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 2260/44 by parameter estimation
• CPC Class Codes: B60L 3/12 Recording operating variables ; Monitoring of operating variables
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/367 Software therefor, e.g. for battery testing using modelling or look-up tables
• CPC Class Codes: G01R 31/3828 using current integration
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A residual capacity calculation apparatus for a battery includes a current detection device to detect a charge/discharge current of the battery and a voltage detection device to detect an open circuit voltage of the battery, and a controller. The controller is configured to calculate a first residual capacity based on an integrated value of the charge/discharge current of the battery, calculate a second residual capacity based on the open circuit voltage of the battery, 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, and increase the blend rate as the deviation between the first residual capacity and the second residual capacity increases.

Claims

1. 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.

2. The control device for an electric vehicle according to claim 1, wherein the battery controller is further programmed to:

calculate a change range of the first residual capacity in one calculation period based on an integrated value of a detection value of the charge/discharge current in the one calculation period, a full charge capacity determined in advance, and an error estimated value including any one of a detection error of the current sensor or an error of the full charge capacity; and

limit the second residual capacity to a value within an estimation value limit range to calculate a value as the first residual capacity.

3. The control device for an electric vehicle according to claim 1, wherein the post-combination residual capacity is a weighted sum of the first residual capacity and the second residual capacity.

4. A control method for an electric vehicle,

a battery of the vehicle comprising a current sensor adapted to detect a charge/discharge current of the battery, and a voltage sensor adapted to detect an open circuit voltage of the battery;

the control method comprising;

a first residual capacity calculation step of calculating a first residual capacity based on an integrated value of the charge/discharge current of the battery detected by the current sensor;

a second residual capacity calculation step of calculating a second residual capacity based on the open circuit voltage of the battery detected by the voltage sensor;

a step of setting a blend rate larger 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;

a third residual capacity calculation step of calculating 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;

a step of calculating a detection value of the residual capacity of the battery by using the post-combination residual capacity calculated by the third residual capacity calculation step as the 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;

a step of limiting, when it is determined that the post-combination residual capacity is insufficient, an electric power consumption of an electric load arranged to operate with electric power supplied from the battery and causing a meter to display the post-combination residual capacity to a driver.

5. The method for an electric vehicle according to claim 4, wherein the post-combination residual capacity is a weighted sum of the first residual capacity and the second residual capacity.