Electricity storage control apparatus and method of controlling electricity storage

• US 8,180,508 B2
• Filed: 09/03/2007
• Issued: 05/15/2012
• Est. Priority Date: 09/04/2006
• Status: Expired due to Fees

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Kawai, Toshiyuki
• Primary Examiner(s): Black, Thomas
• Assistant Examiner(s): Lewandroski, Sara
• Application Number:
  US12/374,720
• Publication Number:
  US 20090319108A1
• Time in Patent Office: 1,716 Days
• Field of Search: 324426-427, 324/430, 701/22, 320/132, 320/149, 320/104
• US Class Current: 701/22
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 7/16 for vehicles comprising converters between the power source and the motor
• CPC Class Codes: H02J 7/1438 in combination with power supplies for loads other than batteries
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

An electricity storage control apparatus that controls an electricity storage device mounted on a vehicle includes control device that changes a target state of charge, which is used as the target of a state of charge of the electricity storage device, and calculating device that calculates an amount of decrease in voltage across the electricity storage device caused as the vehicle is operated. The control device increases the target state of charge if a decreased voltage value, which is lower than a reference voltage value of the electricity storage device by the voltage decrease amount calculated by the calculating device, is equal to or lower than a threshold.

Claims

1. An electricity storage control apparatus that controls an electricity storage device mounted on a vehicle, comprising:

a control device to change a target state of charge, which is used as the target of a state of charge of the electricity storage device; and

a calculating device to calculate an amount of decrease in voltage across the electricity storage device caused as the vehicle is operated,

wherein the control device increases the target state of charge if a decreased voltage value, which is lower than a reference voltage value of the electricity storage device by the voltage decrease amount calculated by the calculating device, is equal to or lower than a threshold,

wherein the reference voltage value corresponds to a voltage value at the intersection of a maximum electricity storage device power output curve with a current-voltage characteristic line of the electricity storage device at the target state of charge, and

wherein the threshold is a minimum voltage value for the electricity storage device set based on the vehicle.

2. The electricity storage control apparatus according to claim 1, wherein:

the control device decreases the target state of charge if the decreased voltage value is larger than the threshold.

3. The electricity storage control apparatus according to claim 1 wherein:

a reference power output from the electricity storage device generated at the reference voltage value corresponds to a maximum vehicle power output.

4. The electricity storage control apparatus according to claim 3, wherein:

a power output from the electricity storage device, which is used when calculating the voltage decrease amount of the electricity storage device caused as the vehicle is operated, is smaller than the reference power output.

5. The electricity storage control apparatus according to claim 3, wherein:

a power output from the electricity storage device, which is used when calculating the voltage decrease amount of the electricity storage device caused as the vehicle is operated, is in a range from 70% to 80% of the reference power output.

6. The electricity storage control apparatus according to claim 1, further comprising:

a current detecting device to detect a value of electric current flowing through the electricity storage device; and

a voltage detecting device to detect a value of voltage across the electricity storage device,

wherein the control device, when the electricity storage device is discharging, calculates a current-voltage characteristic based on the current value detected by the current detecting device and the voltage value detected by the voltage detecting device, and estimates the reference voltage value based on the calculated current-voltage characteristic.

7. The electricity storage control apparatus according to claim 1, wherein:

the control device changes the target state of charge within a range of 40% to 80%.

8. A method of controlling an electricity storage device that changes a target state of charge, which is used as the target of the electricity storage device mounted on a vehicle, the method comprising:

calculating an amount of decrease in voltage across the electricity storage device caused as the vehicle is operated;

determining whether a decreased voltage value, which is lower than a reference voltage value of the electricity storage device by the voltage decrease amount calculated, is equal to or lower than a threshold; and

increasing the target state of charge if it is determined that the decreased voltage value is equal to or lower than the threshold,

wherein the reference voltage value corresponds to a voltage value at the intersection of a maximum electricity storage device power output curve with a current-voltage characteristic line of the electricity storage device at the target state of charge, and

wherein the threshold is a minimum voltage value for the electricity storage device set based on the vehicle.