Status detector for power supply, power supply, and initial characteristic extracting device for use with power supply

• US 7,622,894 B2
• Filed: 02/06/2006
• Issued: 11/24/2009
• Est. Priority Date: 03/07/2005
• Status: Active Grant

• Current Assignee: Vehicle Energy Japan, Inc. (Nissan Motor Co., Ltd.)
• Original Assignee: Hitachi Vehicle Energy, Ltd. (Hitachi, Ltd.)
• Inventors: Takahashi, Hirotaka, Emori, Akihiko, Kudo, Akihiko, Kawahara, Youhei, Shida, Masami, Yamauchi, Shuko
• Primary Examiner(s): Tso; Edward
• Assistant Examiner(s): WILLIAMS, ARUN C
• Application Number:
  US11/347,388
• Publication Number:
  US 20060202857A1
• Time in Patent Office: 1,387 Days
• Field of Search: 320/127, 320/137, 320/165, 320/153, 324/434, 324/430, 324/431, 324/432, 324/522
• US Class Current: 320/127
• 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 2250/16 by display
• CPC Class Codes: B60L 3/0038 relating to sensors
• CPC Class Codes: B60L 50/40 using propulsion power supplied by capacitors
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: G01R 31/3648 comprising digital calculation means, e.g. for performing an algorithm
• CPC Class Codes: G01R 31/3842 combining voltage and current measurements
• CPC Class Codes: H02J 7/0049 Detection of fully charged condition
• CPC Class Codes: H02J 7/005 Detection of state of health [SOH]
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

In a status detector for a power supply, a power supply, and an initial characteristic extracting device for use with the power supply, a measuring unit obtains measured values of at least current, voltage and temperature of the electricity accumulating unit. A processing unit executes status detection of the electricity accumulating unit by using the measured values and the characteristic information of the electricity accumulating unit which is stored in a memory unit. A discrepancy detecting unit detects the presence of a discrepancy away from a theoretical value when a result of the status detection is changed over a predetermined threshold or reversed with respect to the measured values. A modifying unit modifies the characteristic information depending on the detected discrepancy.

Claims

1. A status detector for a power supply, comprising:

measuring means for obtaining measured values of at least current, voltage and temperature of electricity accumulating means;

memory means for storing characteristic information of said electricity accumulating means;

processing means for executing status detection of said electricity accumulating means by using the measured values and the characteristic information of said electricity accumulating means which is stored in said memory means to calculate a value of status detection;

discrepancy detecting means for detecting from a theoretical value when the calculated value of the status detection obtained by said processing means is changed over a predetermined threshold or reversed with respect to the measured values obtained by said measuring means; and

modifying means for modifying the characteristic information used subsequently for status detection value calculation by said processing means and stored in said memory means depending on the discrepancy detected by said discrepancy detecting means;

wherein said modifying means make modification to increase internal DC resistance of said electricity accumulating means as one item of the characteristic information when the result of the status detection is changed over the predetermined threshold, and modification to decrease the internal DC resistance of said electricity accumulating means as one item of the characteristic information when the result of the status detection is reversed with respect to the measured values obtained by said measuring means.

2. The status detector for the power supply according to claim 1, wherein the threshold used by said discrepancy detecting means for determining the presence of a discrepancy is a maximum amount in change of the state of charge of said electricity accumulating means, which is obtained from chargeable and dischargeable maximum current values Icmax, Idmax and fully charged capacity Qmax decided from performance of said electricity accumulating means.

3. The status detector for the power supply according to claim 2, wherein the chargeable and dischargeable maximum current values of said electricity accumulating means are changed depending on the present state of charge and temperature of said electricity accumulating means and whether said electricity accumulating means is charged or discharged, and the maximum amount in change of the state of charge of said electricity accumulating means, which is used as the threshold by said discrepancy detecting means, is changed correspondingly.

4. The status detector for the power supply according to claim 1, wherein after the presence of a discrepancy has been detected by said discrepancy detecting means, said modifying means modifies, among the characteristic information stored in said memory means, the internal DC resistance corresponding to one or more states of said electricity accumulating means, including the state of charge and/or temperature thereof.

5. The status detector for the power supply according to claim 4, wherein when said discrepancy detecting means detects, based on the result of the status detection, a discrepancy away from the theoretical value which is changed over the predetermined threshold, said modifying means determines characteristic information causing the detected change to be matched with the threshold, sets a difference between the characteristic information used for detecting the discrepancy and the newly determined characteristic information as a modification amount, and modifies the internal DC resistance while dynamically changing the modification amount.

6. The status detector for the power supply according to claim 1, wherein said processing means detects the state of charge of said electricity accumulating means again by using the modified characteristic information.

7. The status detector for the power supply according to claim 1, wherein said processing means comprises:

voltage computing means for executing the status detection of said electricity accumulating means by using the voltage obtained as one of the measured values and the characteristic information of said electricity accumulating means which is stored in said memory means;

current integrating means for executing the status detection of said electricity accumulating means by using the current obtained as one of the measured values and the characteristic information of said electricity accumulating means which is stored in said memory means;

IR error determining means for determining an influence of generated error by using the current obtained as one of the measured values and internal DC resistance as one item of the characteristic information of said electricity accumulating means which is stored in said memory means; and

weight deciding means for, based on the error influence determined by said IR error determining means, deciding a weight for the status of said electricity accumulating means detected by said voltage computing means and a weight for the status of said electricity accumulating means detected by said current computing means,

wherein the status detection of said electricity accumulating means is executed such that;

the weight for said voltage computing means is decreased and the weight for said current computing means is increased under a situation where the internal DC resistance is increased, including a low state of charge, a low temperature state and a deteriorated state, or when said electricity accumulating means is charged or discharged at a large current, and

the weight for said voltage computing means is increased and the weight for said current computing means is decreased under a situation where the internal DC resistance is reduced, or when said electricity accumulating means is charged or discharged at a small current.

8. The status detector for the power supply according to claim 1, further comprising:

characteristic extracting means for obtaining the measured values of said electricity accumulating means, automatically executing the status detection of said electricity accumulating means including the state of charge and/or temperature and whether said electricity accumulating means is charged or discharged, analyzing voltage changes caused upon application of current to automatically obtain information of said electricity accumulating means including internal DC resistance, polarization voltage, fully charged capacity, and a delay time of polarization voltage drop, and setting the obtained information as the characteristic information corresponding to the detected status of said electricity accumulating means.

9. The status detector for the power supply according to claim 8, wherein said processing means executes the status detection of said electricity accumulating means by using the characteristic information obtained by said characteristic extracting means,

said discrepancy detecting means monitors whether the result obtained by said processing means contains a discrepancy away from the theoretical value,

said modifying means modifies the characteristic information obtained by said characteristic extracting means depending on the monitoring of said discrepancy detecting means, and

said processing means executes the status detection of said electricity accumulating means again by using the modified characteristic information.

10. The status detector for the power supply according to claim 1, further comprising deterioration determining means for monitoring the characteristic information of said electricity accumulating means which has been modified by said modifying means, and determining the end of life of said electricity accumulating means when the monitored characteristic information exceeds a predetermined threshold.

11. A power supply comprising:

electricity accumulating means capable of being charged and discharged;

measuring means capable of obtaining measured values of at least current, voltage and temperature of said electricity accumulating means; and

status detecting means for detecting status of said electricity accumulating means, said status detecting means comprising;

memory means for storing characteristic information of said electricity accumulating means;

processing means for executing status detection of said electricity accumulating means by using the measured values and the characteristic information of said electricity accumulating means which is stored in said memory means to calculate a value of status detection;

discrepancy detecting means for detecting from a theoretical value when the calculated value of the status detection obtained by said processing means is changed over a predetermined threshold or reversed with respect to the measured values obtained by said measuring means; and

modifying means for modifying the characteristic information used subsequently for status detection value calculation by said processing means and stored in said memory means depending on the discrepancy detected by said discrepancy detecting means wherein said modifying means make modification to increase internal DC resistance of said electricity accumulating means as one item of the characteristic information when the result of the status detection is changed over the predetermined threshold, and modification to decrease the internal DC resistance of said electricity accumulating means as one item of the characteristic information when the result of the status detection is reversed with respect to the measured values obtained by said measuring means.

12. An initial characteristic extracting device for use with a power supply, comprising:

electricity accumulating means capable of being charged and discharged;

measuring means for obtaining information of said electricity accumulating means during charge and discharge; and

status detecting means for detecting status of said electricity accumulating means,

said status detecting means comprising measuring means capable of obtaining measured values of at least current, voltage and temperature of said electricity accumulating means;

measuring means capable of obtaining measured values of at least current, voltage and temperature of said electricity accumulating means;

memory means for storing characteristic information of said electricity accumulating means;

processing means for executing status detection of said electricity accumulating means by using the measured values and the characteristic information of said electricity accumulating means which is stored in said memory means to calculate a value of status detection;

discrepancy detecting means for detecting from a theoretical value; and

modifying means for modifying the characteristic information used subsequently for status detection value calculation by said processing means and stored in said memory means depending on the discrepancy detected by said discrepancy detecting means,

said initial characteristic extracting device further comprising a charging/discharging device for charging and discharging said electricity accumulating means in accordance with a predetermined pulse pattern,

said charging/discharging device performing charge and discharge of said electricity accumulating means,

said measuring means measuring the information of said electricity accumulating means during the charge and the discharge,

said processing means detecting the status of said electricity accumulating means by using the measured values and the characteristic information of said electricity accumulating means which is stored in said memory means,

said discrepancy detecting means detecting the presence of a discrepancy of the detected status away from the theoretical value, and

said modifying means modifying the characteristic information such that the characteristic information is converged within a certain range and the converged characteristic information is extracted as an initial characteristic of said electricity accumulating means wherein said modifying means make modification to increase internal DC resistance of said electricity accumulating means as one item of the characteristic information when the result of the status detection is changed over the predetermined threshold, and modification to decrease the internal DC resistance of said electricity accumulating means as one item of the characteristic information when the result of the status detection is reversed with respect to the measured values obtained by said measuring means.

13. The initial characteristic extracting device for use with the power supply according to claim 12, further comprising:

characteristic extracting means for obtaining the measured values of said electricity accumulating means, automatically executing the status detection of said electricity accumulating means including the state of charge and/or temperature and whether said electricity accumulating means is charged or discharged, analyzing voltage changes caused upon application of current to automatically obtain information of said electricity accumulating means including internal DC resistance, polarization voltage, fully charged capacity, and a delay time of polarization voltage drop, and setting the obtained information as the characteristic information corresponding to the detected status of said electricity accumulating means,

said characteristic extracting means analyzing the measured values to automatically extract the characteristic information,

said processing means executing the status detection by using the extracted characteristic information,

said discrepancy detecting means monitoring the presence of a discrepancy of the detected status away from the theoretical value, and

said modifying means modifying the characteristic information upon the presence of discrepancy such that the modified characteristic information is extracted as an initial characteristic of said electricity accumulating means.

14. An initial characteristic extracting device for use with a power supply, comprising:

plurality of electricity accumulating means capable of being charged and discharged;

measuring means for obtaining information of said electricity accumulating means during charge and discharge; and

status detecting means for detecting status of said electricity accumulating means, said status detecting means comprising;

memory means for storing characteristic information of said electricity accumulating means;

processing means for executing status detection of said electricity accumulating means by using the measured values and the characteristic information of said electricity accumulating means which is stored in said memory means to calculate a value of status detection;

discrepancy detecting the presence of a discrepancy away means for detecting from a theoretical value; and

modifying means for modifying the characteristic information used subsequently for status detection value calculation by said processing means and stored in said memory means depending on the discrepancy detected by said discrepancy detecting means, said modifying means make modification to increase internal DC resistance of said electricity accumulating means as one item of the characteristic information when the result of the status detection is changed over the predetermined threshold, and modification to decrease the internal DC resistance of said electricity accumulating means as one item of the characteristic information when the result of the status detection is reversed with respect to the measured values obtained by said measuring means;

said initial characteristic extracting device further comprising a charge/discharge control unit for charging and discharging a plurality of electricity accumulating means therebetween in accordance with a predetermined pulse pattern,

said charging/discharging device performing charge and discharge between said plurality of electricity accumulating means, and

said measuring means obtaining measured values during the charge and the discharge between said plurality of electricity accumulating means such that an initial characteristic of said electricity accumulating means is extracted using the measured values.