Method of disconnecting secondary battery and electric power supply system

• US 9,987,931 B2
• Filed: 02/13/2017
• Issued: 06/05/2018
• Est. Priority Date: 02/15/2016
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Oya, Ryosuke
• Primary Examiner(s): Ro, Bentsu
• Application Number:
  US15/430,784
• Publication Number:
  US 20170232852A1
• Time in Patent Office: 477 Days
• Field of Search: 318139, 318442, 318479, 318490, 318500, 318504
• CPC Class Codes: B60L 15/007 Physical arrangements or structures of drive train converters specially adapted for the propulsion motors of electric vehicles
• CPC Class Codes: B60L 2210/10 DC to DC converters
• CPC Class Codes: B60L 2240/527 Voltage
• CPC Class Codes: B60L 2240/529 Current
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 3/04 Cutting off the power supply under fault conditions protective devices and circuit arrangements in general H01H; H02H
• CPC Class Codes: B60L 50/51 characterised by AC-motors
• CPC Class Codes: B60L 58/10 for monitoring or controlling batteries
• CPC Class Codes: B60L 58/40 for controlling a combination of batteries and fuel cells
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence
• CPC Class Codes: H02J 7/0068 Battery or charger load switching, e.g. concurrent charging and load supply H02J7/0013 takes precedence
• CPC Class Codes: H02P 27/06 using dc to ac converters or inverters H02P27/05 takes precedence
• CPC Class Codes: Y02T 10/64 Electric machine technologies in electromobility
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility
• CPC Class Codes: Y02T 90/40 Application of hydrogen technology to transportation, e.g. using fuel cells

Abstract

A method of disconnecting a secondary battery which disconnects the secondary battery from an electric power supply path in an electric power supply system performs shutting off a flow of a current to a secondary battery side through a converter after it is detected that there is an abnormality in the secondary battery, and when it is determined that the voltage of the power storage unit is equal to or less than the voltage of the secondary battery by the predetermined value, maintaining a connection of the secondary battery to the electric power supply path and when it is determined that the voltage of the power storage unit is greater than the voltage of the secondary battery by the predetermined value, operating a relay to disconnect the secondary battery from the electric power supply path.

Claims

1. A method of disconnecting a secondary battery which disconnects the secondary battery from an electric power supply path in an electric power supply system, the electric power supply system being able to supply electric power from the secondary battery to a motor for traveling through the electric power supply path, and the electric power supply system including a converter provided in the electric power supply path between the secondary battery and the motor for traveling, a power storage unit provided at a location closer to the motor for traveling than the converter in the electric power supply path, a relay provided at a location closer to the secondary battery than the converter in the electric power supply path, and a control unit configured to control the motor for traveling, the converter, and the relay, the method comprising:

detecting a presence or absence of an abnormality in the secondary battery;

shutting off a flow of a current to a secondary battery side through the converter after it is detected that there is an abnormality in the secondary battery;

determining whether or not a voltage of the power storage unit is greater than a voltage of the secondary battery by a predetermined value; and

when it is determined that the voltage of the power storage unit is equal to or less than the voltage of the secondary battery by the predetermined value, maintaining a connection of the secondary battery to the electric power supply path and when it is determined that the voltage of the power storage unit is greater than the voltage of the secondary battery by the predetermined value, operating the relay to disconnect the secondary battery from the electric power supply path.

2. The method according to claim 1, further comprising:

in a case where it is determined that the voltage of the power storage unit is equal to or less than the voltage of the secondary battery by the predetermined value, charging the power storage unit with regeneration of the motor for traveling until the voltage of the power storage unit becomes greater than the voltage of the secondary battery by the predetermined value.

3. The method according to claim 1, wherein

in a case where it is determined that the voltage of the power storage unit is greater than the voltage of the secondary battery by the predetermined value, all accessories of the electric power supply system are stopped, and then, the relay is operated to disconnect the secondary battery from the electric power supply path.

4. The method according to claim 1, wherein

all accessories of the electric power supply system are driven at a minimum level set in advance and power consumption is minimized to shut off the flow of the current to the secondary battery side through the converter.

5. The method according to claim 1, wherein

the predetermined value is a voltage value which is determined from a precision in a sensor configured to measure the voltage or a capacity of the power storage unit.

6. An electric power supply system which is able to supply electric power from a secondary battery to a motor for traveling through an electric power supply path, the electric power supply system comprising:

a converter provided in the electric power supply path between the secondary battery and the motor for traveling;

a power storage unit provided at a location closer to the motor for traveling than the converter in the electric power supply path;

a relay provided at a location closer to the secondary battery than the converter in the electric power supply path; and

a control unit configured to control the motor for traveling, the converter, and the relay,

wherein the control unit is configured to

i) detect an abnormality in the secondary battery,

ii) shut off a flow of a current to a secondary battery side through the converter after an abnormality in the secondary battery is detected,

iii) determine whether or not a voltage of the power storage unit is greater than a voltage of the secondary battery by a predetermined value, and

iv) when it is determined that the voltage of the power storage unit is equal to or less than the voltage of the secondary battery by the predetermined value, maintain a connection of the secondary battery to the electric power supply path and when it is determined that the voltage of the power storage unit is greater than the voltage of the secondary battery by the predetermined value, operate the relay to disconnect the secondary battery from the electric power supply path.

7. The electric power supply system according to claim 6, wherein

the control unit is configured to, in a case where it is determined that the voltage of the power storage unit is equal to or less than the voltage of the secondary battery by the predetermined value, charge the power storage unit by regeneration of the motor for traveling until the voltage of the power storage unit becomes greater than the voltage of the secondary battery by the predetermined value.