Storage battery managing apparatus and vehicle controlling apparatus providing the same

• US 7,755,331 B2
• Filed: 10/17/2007
• Issued: 07/13/2010
• Est. Priority Date: 10/19/2006
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Takahashi, Hirotaka, Emori, Akihiko, Kawahara, Youhei, Shida, Masami, Yamauchi, Shuko, Aoshima, Yoshinori
• Primary Examiner(s): PHAN, HAU VAN
• Application Number:
  US11/873,914
• Publication Number:
  US 20080156551A1
• Time in Patent Office: 1,000 Days
• Field of Search: 180/65.1, 320/164, 320/118, 320/132, 320/106, 320/136, 320/159, 320/161, 320/162, 320/151, 320/152, 324/434, 324/429, 324/433, 324/127, 324/427, 701/36, 701/22
• US Class Current: 320/164
• 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 50/51 characterised by AC-motors
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 58/22 Balancing the charge of battery modules
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A storage battery managing apparatus which ensures charge-discharge control of a storage battery in consideration of state variation of each unit cell even if the battery pack includes a number of component unit cells, and a vehicle controlling apparatus providing the same. A storage battery includes a plurality of chargeable-dischargeable unit cells connected in which battery management ICs detect the cell voltage of each unit cell, a voltage sensor detects a storage battery voltage and a current sensor detects currents to be charged and discharged in the storage battery. A degree of SOC imbalance is obtained by use of detected cell voltage of each unit cell when the storage battery is being neither charged nor discharged.

Claims

1. A storage battery managing apparatus comprising:

a storage battery having a plurality of chargeable-dischargeable unit cells connected therein;

cell voltage detection means for detecting the voltage of each unit cell;

storage battery voltage detection means for detecting the storage battery voltage; and

current detection means for detecting a current flowing under no-load conditions or charge-discharge conditions of said storage battery;

wherein the storage battery managing apparatus includes processing means for obtaining a degree of SOC imbalance by use of the cell voltage of each unit cell detected by said cell voltage detection means when said storage battery is being neither charged nor discharged; and

for calculating highest and lowest SOCs from the average SOC obtained from the storage battery voltage detected by said storage battery voltage detection means and the degree of SOC imbalance when said storage battery is being charged or discharged, thereby managing charge-discharge current or charge-discharge power.

2. The storage battery managing apparatus according to claim 1, wherein:

the processing means is configured for;

converting the cell voltage of each unit cell detected by said cell voltage detection means to SOC when said storage battery is being neither charged nor discharged;

detecting an average SOC of said storage battery from an average of the plurality of SOCs;

detecting highest and lowest SOCs from the plurality of SOCs;

calculating Δ

SOC1 by use of the highest and average SOCs (Highest SOC-Average SOC); and

calculating Δ

SOC2 by use of the average and lowest SOCs (Average SOC-Lowest SOC), thereby detecting the degree of SOC imbalance of said storage battery.

3. The storage battery managing apparatus according to claim 2, wherein:

the processing means is configured for;

calculating an estimated highest SOC (SOCmax) from the average SOC obtained from the storage battery voltage detected by said storage battery voltage detection means and the degree of SOC imbalance, Δ

SOC1, when said storage battery is being charged or discharged; and

calculating an estimated lowest SOC (SOCmin) from the average SOC and the degree of SOC imbalance, Δ

SOC2.

4. The storage battery managing apparatus according to claim 3, wherein:

the processing means determines a permissible charge current or permissible charge power based on the estimated highest SOC, and determines a permissible discharge current or permissible discharge power based on the estimated lowest SOC.

5. The storage battery managing apparatus according to claim 4, wherein:

the processing means is configured for

obtaining an impedance of said storage battery corresponding to the estimated highest SOC;

determining a current value or a power value, with which said storage battery having an impedance of the estimated highest SOC does not reach a maximum voltage (control target), as a permissible charge current or permissible charge power;

obtaining an impedance of said storage battery corresponding to the estimated lowest SOC; and

determining a current value or a power value, with which said storage battery having an impedance of the estimated lowest SOC does not fall below a minimum voltage (control target), as a permissible discharge current or permissible discharge power.