ELECTRICAL STORAGE SYSTEM, AND CONTROL METHOD FOR ELECTRICAL STORAGE SYSTEM

• US 20140111122A1
• Filed: 10/22/2013
• Published: 04/24/2014
• Est. Priority Date: 10/22/2012
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: KAWASHIMA, Hironobu, TANABE, Yukinari
• Granted Patent: US 9,252,608 B2
• Time in Patent Office: Days
• US Class Current: 318/139
• CPC Class Codes: B60L 3/00 Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption methods or circuit arrangements for monitoring or controlling batteries or fuel cells B60L58/00
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: G01R 31/3835 involving only voltage measurements
• CPC Class Codes: G01R 31/396 Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
• CPC Class Codes: H02J 2310/48 for electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0025 Sequential battery discharge in systems with a plurality of batteries
• CPC Class Codes: H02J 7/00304 Overcurrent protection
• CPC Class Codes: H02J 7/00306 Overdischarge protection
• CPC Class Codes: H02J 7/00308 Overvoltage protection
• CPC Class Codes: H02J 7/0063 with circuits adapted for supplying loads from the battery
• 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 first electrical storage stack is connected in series with a second electrical storage stack. A current interrupter is configured to interrupt a current path by being removed from the current path. First and second detection line are respectively connected to first and second terminals of the first electrical storage stack. The second electrical storage stack is connected to the second terminal of the first electrical storage stack via the current interrupter. A third detection line is connected to a portion of the current path, located on the second electrical storage stack side of the current interrupter. A controller is configured to control charging and discharging operations of each of the first and second electrical storage stacks on the basis of the voltage of the first electrical storage stack, the voltage being detected via the first detection line and the third detection line.

Claims

1. An electrical storage system configured to supply electric power to a drive motor for a vehicle, the electrical storage system comprising:

a first electrical storage stack constituted by a plurality of electrical storage elements;

a second electrical storage stack constituted by a plurality of electrical storage elements and connected in series with the first electrical storage stack;

a voltage monitoring unit including a plurality of detection lines, the voltage monitoring unit being configured to receive potentials of both positive and negative electrode terminals of each of the first and second electrical storage stacks via the detection lines and detect voltages of the first and second electrical storage stacks;

a current interrupter detachably provided in a current path between the first and second electrical storage stacks, and configured to interrupt the current path by being removed from the current path; and

a controller configured to control charging and discharging operations of each of the first and second electrical storage stacks, wherein

the detection lines include a first detection line, a second detection line and a third detection line,

the first detection line is connected to a first terminal of the first electrical storage stack,

the second detection line is connected to a second terminal of the first electrical storage stack,

the second electrical storage stack is connected to the second terminal of the first electrical storage stack via the current interrupter,

the third detection line is connected to a portion of the current path, located on the second electrical storage stack side of the current interrupter, and

the controller is configured to control charging and discharging operations of each of the first and second electrical storage stacks on the basis of the voltage of the first electrical storage stack, which is detected via the first detection line and the third detection line.

2. The electrical storage system according to claim 1, wherein

the voltage monitoring unit further includes a first capacitor and a voltage detection unit,

the first capacitor is connected between the detection lines, and is configured to be charged on the basis of a voltage between the detection lines,

the voltage detection unit is connected between both electrodes of the first capacitor, and is configured to detect a voltage of the first capacitor,

the third detection line is connected to one of the electrodes of the first capacitor, and

the second detection line is connected to the one of the electrodes.

3. The electrical storage system according to claim 2, wherein

the detection lines further include a fourth detection line and a fifth detection line,

the fourth detection line is connected to a first terminal of the second electrical storage stack,

the fifth detection line is connected to a second terminal of the second electrical storage stack,

one end of the third detection line is connected to the fourth detection line,

the other end of the third detection line is connected to the first capacitor, and

the third detection line is a detection line branched off from the fourth detection line.

4. The electrical storage system according to claim 1, wherein

the voltage monitoring unit further includes a plurality of switches respectively provided in the detection lines, and

the controller is configured not to carry out charging and discharging operations of each of the first and second electrical storage stacks when the voltage of the first electrical storage stack, detected at the time when the switch in the first detection line and the switch in the third detection line are turned on, is 0.

5. The electrical storage system according to claim 1, further comprising:

a system main relay configured to allow connection between the drive motor and one of the first electrical storage stack and the second electrical storage stack, wherein

the voltage monitoring unit is configured to, when an ignition switch is turned on, detect the voltage of the first electrical storage stack via the first detection line and the third detection line before the system main relay is turned on,

the controller is configured to restrict switching of the system main relay from an off state to an on state, and

when the ignition switch is turned on, the electrical storage system is started up.

6. The electrical storage system according to claim 5, further comprising:

a second capacitor connected in parallel with the first electrical storage stack and the second electrical storage stack via the system main relay.

7. The electrical storage system according to claim 1, further comprising:

a system main relay configured to allow connection between the drive motor and one of the first electrical storage stack and the second electrical storage stack, wherein

the controller is configured to restrict switching of the system main relay when the voltage of the first electrical storage stack, which is detected via the first detection line and the third detection line, is not detected.

8. The electrical storage system according to claim 1, wherein

the controller is configured to prohibit charging and discharging operations of each of the first and second electrical storage stacks on the basis of the voltage of the first electrical storage stack, which is detected via the first detection line and the third detection line.

9. The electrical storage system according to claim 1, wherein

the voltage monitoring unit further includes a plurality of switches respectively provided in the detection lines, and

the controller is configured to prohibit charging and discharging operations of each of the first and second electrical storage stacks when the voltage of the first electrical storage stack, which is detected at the time when the switch in the first detection line and the switch in the third detection line are turned on, is lower than an open-circuit voltage of the first electrical storage stack.

10. A control method for an electrical storage system including a first electrical storage stack of which a first terminal and a second terminal are respectively connected to a first detection line and a second detection line;

a second electrical storage stack connected in series with the first electrical storage stack at the second terminal via a current interrupter; and

the current interrupter configured to interrupt a current path between the first electrical storage stack and the second electrical storage stack by being removed from the current path, the electrical storage system being configured to supply electric power to a drive motor for a vehicle, the control method comprising;

detecting a voltage of the first electrical storage stack via the first detection line and a third detection line, the third detection line being connected to a portion of the current path, the portion being located on the second electrical storage stack side of the current interrupter; and

controlling charging and discharging operations of each of the first and second electrical storage stacks on the basis of the detected voltage of the first electrical storage stack.

11. The control method according to claim 10, further comprising:

prohibiting charging and discharging operations of each of the first and second electrical storage stacks when the voltage of the first electrical storage stack, which is detected via the first detection line and the third detection line, is 0.

12. The control method according to claim 10, further comprising:

prohibiting charging and discharging operations of each of the first and second electrical storage stacks when the voltage of the first electrical storage stack, which is detected via the first detection line and the third detection line, is lower than an open circuit voltage of the first electrical storage stack.