Electrical storage system, and control method for electrical storage system

• US 9,252,608 B2
• Filed: 10/22/2013
• Issued: 02/02/2016
• 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
• Primary Examiner(s): Santana, Eduardo Colon
• Assistant Examiner(s): AGARED, GABRIEL T
• Application Number:
  US14/059,854
• Publication Number:
  US 20140111122A1
• Time in Patent Office: 833 Days
• Field of Search: 318/139, 320/118, 320/119, 320/134
• US Class Current: 1/1
• 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 that supplies 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 capacitor that is charged by receiving potentials of positive and negative electrodes of each of the electrical storage stacks via detection lines, and a voltage detection unit that is connected to both ends of the capacitor, and detects a voltage value of the capacitor;

a current interrupter that is detachably provided in a current path connecting the first electrical storage stack and the second electrical storage stack, and interrupts the current path by being removed from the current path; and

a controller that controls charging and discharging operations of each of the first storage stack and the second electrical storage stack, wherein

the detection lines include;

a first detection line having one end connected to a positive electrode terminal of the first electrical storage stack, and the other end connected to one end of the capacitor;

a second detection line having one end connected to a negative electrode terminal of the first electrical storage stack, and the other end connected to the other end of the capacitor;

a third detection line having one end connected to a positive electrode terminal of the second electrical storage stack, and the other end connected to the one end of the capacitor;

a fourth detection line having one end connected to a negative electrode terminal of the second electrical storage stack, and the other end connected to the other end of the capacitor; and

a fifth detection line having one end connected to the third detection line, and the other end connected to the second detection line, and

the controller executes control such that the charging and discharging operations of each of the first electrical storage stack and the second electrical storage stack are not carried out, on the voltage value of the capacitor, which is detected via the first detection line and the fifth detection line.

2. 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.

3. 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.

4. 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.

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

a system main relay that allows connection between the first electrical storage stack and the second electrical storage stack, and the drive motor, wherein

the voltage monitoring unit detects, when an ignition switch of the vehicle is turned on, the voltage value of the capacitor via the first detection line and the fifth detection line before the system main relay is turned on, and

the controller executes the control such that the charging and discharging operations of each of the first electrical storage stack and the second electrical storage stack are not carried out by restricting switching of the system main relay from an off state to an on state, on the basis of the voltage value of the capacitor, which is detected via the first detection line and the fifth detection line.

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, wherein

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

the controller executes the control such that the charging and discharging operations of each of the first electrical storage stack and the second electrical storage stack are not carried out when the voltage value of the capacitor, detected at the time when the switch in the first detection line and the switch in the fifth detection line are turned on, is 0.

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

a system main relay that allows connection between the first electrical storage stack and the second electrical storage stack, and the drive motor, wherein

the voltage monitoring unit detects, when an ignition switch of the vehicle is turned on, the voltage value of the capacitor via the first detection line and the fifth detection line before the system main relay is turned on, and

the controller executes the control such that the charging and discharging operations of each of the first electrical storage stack and the second electrical storage stack are not carried out by restricting switching of the system main relay from an off state to an on state, on the basis of the voltage value of the capacitor, which is detected via the first detection line and the fifth detection line.

9. A control method for an electrical storage system that supplies electric power to a drive motor for a vehicle, 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 capacitor that is charged by receiving potentials of both positive and negative electrode terminals of each of the electrical storage stacks via detection lines, and a voltage detection unit that is connected to both ends of the capacitor, and detects a voltage value of the capacitor; and

a current interrupter that is detachably provided in a current path connecting the first electrical storage stack and the second electrical storage stack, and interrupts the current path by being removed from the current path, wherein

the detection lines include;

a first detection line having one end connected to the positive electrode terminal of the first electrical storage stack, and the other end connected to one end of the capacitor;

a second detection line having one end connected to the negative electrode terminal of the first electrical storage stack, and the other end connected to the other end of the capacitor;

a third detection line having one end connected to the positive electrode terminal of the second electrical storage stack, and the other end connected to the one end of the capacitor;

a fourth detection line having one end connected to the negative electrode terminal of the second electrical storage stack, and the other end connected to the other end of the capacitor; and

a fifth detection line having one end connected to the third detection line, and the other end connected to the second detection line, the control method characterized by comprising;

a step of detecting the voltage value of the capacitor via the first detection line and the fifth detection line; and

a step of executing control such that charging and discharging operations of each of the first electrical storage stack and the second electrical storage stack are not carried out, on the basis of the voltage value of the capacitor.

10. The control method according to claim 9, 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.

11. The control method according to claim 9, 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.