Battery pack controller with specific battery voltage detection

• US 7,583,053 B2
• Filed: 07/11/2006
• Issued: 09/01/2009
• Est. Priority Date: 07/12/2005
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Kamohara, Hideaki
• Primary Examiner(s): Ullah; Akm E
• Assistant Examiner(s): WILLIAMS, ARUN C
• Application Number:
  US11/484,307
• Publication Number:
  US 20070013347A1
• Time in Patent Office: 1,148 Days
• Field of Search: 320/104, 320/150, 320/116, 320/120, 320/134, 320/136, 320/162, 324/433
• US Class Current: 320/106
• CPC Class Codes: B60K 2006/268 Electric drive motor starts the engine, i.e. used as starter motor
• CPC Class Codes: B60K 6/48 Parallel type
• CPC Class Codes: B60L 15/20 for control of the vehicle or its driving motor to achieve a desired performance, e.g. speed, torque, programmed variation of speed
• 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 2240/662 Temperature
• CPC Class Codes: B60L 2260/26 Transition between different drive modes
• 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 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 58/14 Preventing excessive discharging
• CPC Class Codes: B60L 58/21 having the same nominal voltage
• CPC Class Codes: B60W 2510/244 Charge state
• CPC Class Codes: B60W 2510/246 Temperature
• CPC Class Codes: F02N 11/04 the motors being associated with current generators
• CPC Class Codes: F02N 11/0862 characterised by the electrical power supply means, e.g. battery
• CPC Class Codes: F02N 11/0866 comprising several power sources, e.g. battery and capacitor or two batteries
• CPC Class Codes: F02N 2200/061 Battery state of charge [SOC]
• CPC Class Codes: F02N 2200/063 Battery voltage
• CPC Class Codes: F02N 2200/064 : Battery temperature
• CPC Class Codes: H02J 7/0016 : using shunting, discharge or bypass circuits
• CPC Class Codes: H02J 7/0048 : Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: Y02T 10/62 : Hybrid vehicles
• 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 10/7072 : Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 : Electric energy management in electromobility
• CPC Class Codes: Y02T 90/16 : Information or communication technologies improving the operation of electric vehicles

Abstract

The invention provides a specific battery detection means that specifies single batteries believed to be in an excess discharge state during operation of the electric motor for starting the engine, based on data for each battery pack detected prior to starting the engine. With the specific battery detection means, a change in voltage for specific single batteries is measured for a drop in voltage of a single battery by the discharge via the voltage detection means. The specific battery detection means is configured such that if the results of this measurement are outside a predetermined threshold value, the power supplied to the electric motor for starting the engine is limited.

Claims

1. A battery pack controller connected with a battery pack coupled to a motor/generator, the battery pack including a plurality of single batteries to supply electric power to the motor/generator, the battery pack controller comprising:

a voltage detector having a plurality of voltage detection circuits each in electrical communication with a single battery of the plurality of single batteries to detect a voltage of the single battery;

a detected voltage transmitter in electrical communication with each voltage detection circuit of voltage detector to retrieve voltages detected by the plurality of voltage detection circuits and to transmit the detected voltages;

a specific battery detector configured to classify each single battery of the plurality of single batteries as a normal battery if the voltage of the single battery is above a threshold value or as a target battery if the voltage of the single battery is below a threshold value based on the transmitted voltages; and

a power supply controller configured to supply electric power from the battery pack to the motor/generator during internal combustion engine startup, wherein the power supply controller is configured to retrieve voltages from each single battery of the target batteries during internal combustion engine startup using the plurality of voltage detection circuits and limit the electric power supplied to the motor/generator by the battery pack during internal combustion engine startup if any of the target batteries have voltages that are below the threshold value.

2. A battery pack controller as claimed in claim 1, wherein the specific battery detector is configured to identify the single battery of the plurality of single batteries having the lowest power available for discharge, up to a threshold voltage value that acts as an excess discharge limit startup voltage that activates battery discharge limits.

3. A battery pack controller as claimed in claim 1, wherein the power supply controller is configured to calculate an amount of power available for discharge from an open voltage for the specified batteries, an internal resistance calculated from a load cuffent during operation prior the time of calculation, and the threshold voltage value.

4. A battery pack controller as claimed in claim 1, further comprising:

a map of a relationship between a temperature previously measured and an internal resistance;

a temperature detector configured to detect a temperature in the battery pack; and

an internal resistance corrector configured to correct an internal resistance value of a battery in the battery pack based on the temperature detected by the temperature detector according to the map.

5. A battery pack controller as claimed in claim 1, wherein the power supply controller is configured to set a threshold voltage value to control a charge state of the target battery according to one of a vehicle state consisting of one of engine operation or startup, a temperature of the target battery, or combination of battery temperatures, such that

when a battery temperature is lower than a prescribed temperature, an excess discharge is detected, and a voltage threshold value to control a power output and a voltage threshold value prohibiting output are set lower than during a normal state wherein the battery temperature is higher than the prescribed value, and

when the battery temperature is higher that the prescribed temperature, a hypothetical internal resistance is calculated for the charge state for a lower control of the target battery from the calculated internal resistance and the temperature of the target battery, and a maximum battery output value is estimated using the hypothetical internal resistance to determine a control startup voltage threshold value.

6. A battery pack controller as claimed in claim 1, wherein the controller does not stop the internal combustion engine after an ignition switch is turned ON until a battery temperature exceeds a prescribed temperature, except when the ignition switch is turned OFF.

7. A battery pack controller as claimed in claim 1, further comprising:

an output power controller configured to control the charge state of the target battery such that during one of an excess discharge state or an excess charge detection state for each single battery within the battery pack, when an excess discharge or excess charge state is entered due to detection of one of the single batteries being below a first threshold value that is a discharge power control startup voltage, voltage detection for each battery is conducted with a cell controller, and a battery exceeding the threshold value is specified,

wherein voltage detection on the specified battery is conducted one of continuously or at a cycle shorter than the drop in the voltage of the target battery due to discharge, such that the target battery does not reach a second threshold value, wherein the second threshold value is an irreversible deterioration voltage for the target battery.

21. The battery pack controller as claimed in claim 1, wherein the voltages of the normal batteries are not retrieved during internal combustion engine startup.

8. A vehicle equipped with an internal combustion engine, comprising:

a motor/generator capable of starting the internal combustion engine;

a battery pack including a plurality of single batteries that supply power to the motor/generator;

a voltage detector having a plurality of voltage detection circuits each in electrical communication with a single battery of the plurality of single batteries to detect the voltage of each single battery;

a detected voltage transmitter configured to retrieve voltages detected on each single battery of the plurality of single batteries from the plurality of voltage detection circuits and to continuously transmit each voltage detected;

a specific battery detector configured to classify each single battery of the plurality of single batteries as a normal battery if the voltage of the single battery is above a threshold value or as a target battery if the voltage of the single battery is below a threshold value based on the transmitted voltages; and

a power supply controller configured to supply electric power from the battery pack to the motor/generator during internal combustion engine startup, wherein the power supply is configured to retrieve voltages from each single battery of the target batteries during internal combustion engine startup using the plurality of voltage detection circuits and limit the electric power supplied to the motor/generator by the battery pack during internal combustion engine startup if any of the target batteries have voltages that are below the threshold value.

9. A vehicle as claimed in claim 8, wherein the specific battery detector is configured to detect the battery of the plurality of batteries having the lowest power available for discharge, up to a threshold voltage value that acts as an excess discharge limit startup voltage that activates battery discharge limits.

10. A vehicle as claimed in claim 9, wherein the power supply controller is configured to calculate an amount of power available for discharge from an open voltage for the target battery, an internal resistance calculated from a load current during operation prior the time of calculation, and the threshold voltage value.

11. A vehicle as claimed in claim 8, further comprising:

a map of a relationship between a temperature previously measured and an internal resistance;

a temperature detector configured to detect a temperature in the battery pack; and

an internal resistance corrector configured to correct an internal resistance value of the specific battery based on the temperature detected by the temperature detector according to the map.

12. A vehicle as claimed in claim 8, wherein the power supply controller is configured to set a threshold voltage value to control a charge state of the target battery according to one of a vehicle state consisting of one of engine operation or startup, a temperature of the target battery, or combination of battery temperatures, such that

when a battery temperature is lower than a prescribed temperature, an excess discharge is detected, and a voltage threshold value to control a power output and a voltage threshold value prohibiting output are set lower than during a normal state wherein the battery temperature is higher than the prescribed value, and

when the battery temperature is higher that the prescribed temperature, a hypothetical internal resistance is calculated for the charge state for a lower control of the target battery from the calculated internal resistance and the battery temperature, and a maximum battery output value is estimated using the hypothetical internal resistance to determine a control startup voltage threshold value.

13. A vehicle as claimed in claim 8, wherein stopping the internal combustion engine after an initial internal combustion engine startup after an ignition switch is turned ON is not allowed until a battery temperature exceeds a prescribed temperature, except when the ignition switch is turned OFF.

14. A vehicle as claimed in claim 8, further comprising:

an output power controller configured to control the charge state of the target battery such that during one of an excess discharge state or an excess charge detection state for all of the plurality of batteries within the battery pack, when an excess discharge or excess charge state is entered due to detection of a battery of the plurality of batteries outside a first threshold value that is a discharge power control startup voltage, voltage detection for the batteries is conducted with a cell controller, and a battery of the plurality of batteries exceeding the threshold value is specified as the target battery,

wherein voltage detection on the target battery is conducted one of continuously or at a cycle shorter than the drop in the target battery voltage due to discharge, such that the target battery does not reach a second threshold value,

wherein the second threshold value is an irreversible deterioration voltage for the target battery.

15. A battery pack controller connected with a plurality of single batteries that comprise a battery pack and that supply power to a motor/generator for starting an internal combustion engine, comprising:

means for detecting a voltage of each single battery of the plurality of single batteries and supplying power to the motor/generator;

means for retrieving the voltage detected of each single battery of the plurality of single batteries and to transmit the detected voltages;

means for classifying each single battery of the plurality of single batteries as a normal battery if the voltage of the single battery is above a threshold value or as a target battery if the voltage of the single battery is below a threshold value based on the transmitted voltages;

means for retrieving voltages from each single battery of the target batteries using the plurality of voltage detection circuits during internal combustion engine startup; and

means for supplying electric power from the battery pack to the motor/generator during internal combustion engine startup, wherein the power supplied to the motor/generator by the battery pack during internal combustion engine startup is limited if any of the target batteries have voltages that are below the threshold value.

16. A method comprising:

detecting a voltage of each single battery of a plurality of single batteries that comprise a battery pack and that supply power to a motor/generator for starting an internal combustion engine;

retrieving the voltage detected for each single battery of the plurality of batteries;

transmitting each voltage detected;

classifying each single battery of the plurality of single batteries as a normal battery if the voltage of the single battery is above a threshold value or as a target battery if the voltage of the single battery is below a threshold value based on the transmitted voltages;

detecting a voltage for each target battery during internal combustion engine startup; and

supplying electric power from the battery pack to the motor/generator during internal combustion engine startup, wherein the power supplied to the motor/generator by the battery pack during internal combustion engine startup is limited if any of the target batteries have voltages that are below the threshold value.

17. The method of claim 16, further comprising:

calculating an amount of power available for discharge from an open voltage for the specified single batteries, an internal resistance calculated from a load current during operation prior the time of calculation, and the threshold voltage value; and

detecting single batteries of the plurality of single batteries having the lowest power available for discharge, up to a threshold voltage value that acts as an excess discharge limit startup voltage that activates battery discharge limits.

18. The method of claim 16, further comprising:

storing a map of a relationship between a temperature previously measured and an internal resistance;

detecting a temperature in the battery pack; and

correcting an internal resistance value of the specific battery based on the temperature detected by the temperature detector according to the map.

19. The method of claim 16, further comprising:

setting a threshold voltage value to control a charge state of the specific single battery according to one of a vehicle state consisting of one of engine operation or startup, a single battery temperature, or combination of battery temperatures, such that

when a battery temperature is lower than a prescribed temperature, an excess discharge is detected, and a voltage threshold value to control a power output and a voltage threshold value prohibiting output are set lower than during a normal state wherein the battery temperature is higher than the prescribed value, and

when the battery temperature is higher that the prescribed temperature, a hypothetical internal resistance is calculated for the charge state for a lower control of the specified single battery from the calculated internal resistance and the battery temperature, and a maximum battery output value is estimated using the hypothetical internal resistance to determine a control startup voltage threshold value.

20. The method of claim 16, further comprising:

controlling the charge state of the single battery such that during one of an excess discharge state or an excess charge detection state for all of the single batteries within the battery pack, when an excess discharge or excess charge state is entered due to detection of a single battery outside a first threshold value that is a discharge power control startup voltage, voltage detection for the single batteries is conducted with a cell controller, and a single battery exceeding the threshold value is specified; and

conducting voltage detection on the specified single battery one of continuously or at a cycle shorter than the drop in single battery voltage due to discharge, such that the specified single battery does not reach a second threshold value, wherein the second threshold value is an irreversible deterioration voltage for the single battery designated by battery controller software.