Battery management system using non-volatile memory

• US 9,203,248 B2
• Filed: 09/28/2010
• Issued: 12/01/2015
• Est. Priority Date: 09/28/2009
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Ohkawa, Keiichiro, Ueda, Masahiro
• Primary Examiner(s): Dunn, Drew A
• Assistant Examiner(s): Robbins, Jerry D
• Application Number:
  US13/387,396
• Publication Number:
  US 20120175953A1
• Time in Patent Office: 1,890 Days
• Field of Search: 320/116
• US Class Current: 1/1
• CPC Class Codes: B60L 2200/26 Rail vehicles
• 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 2260/44 by parameter estimation
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 58/13 Maintaining the SoC within a determined range
• CPC Class Codes: B60L 58/14 Preventing excessive discharging
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: B60L 58/16 responding to battery ageing, e.g. to the number of charging cycles or the state of health [SoH]
• CPC Class Codes: B60L 58/22 Balancing the charge of battery modules
• 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: G11C 16/225 Preventing erasure, programming or reading when power supply voltages are outside the required ranges
• CPC Class Codes: G11C 29/82 for EEPROMs
• CPC Class Codes: H01M 10/0525 Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
• CPC Class Codes: H01M 10/441 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H02J 7/0016 using shunting, discharge or bypass circuits
• CPC Class Codes: H02J 7/00302 Overcharge protection
• CPC Class Codes: H02J 7/00306 Overdischarge protection
• CPC Class Codes: H02J 7/005 : Detection of state of health [SOH]
• 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 battery system according to the present invention includes: a battery module comprising a plurality of cell groups connected in series, each comprising a plurality of cells connected in series; a plurality of integrated circuits provided to corresponding each cell group of the battery module, that perform detection of terminal voltages of the cells in the corresponding each cell group, and that also perform diagnosis; and a battery controller that, along with issuing commands to the plurality of integrated circuits, also receives results of detection and results of diagnosis by the plurality of integrated circuits; wherein the battery system comprises a writable non-volatile memory, and data is stored in the writable non-volatile memory specifying usage environment of the battery module, including a maximum voltage or a maximum current of the battery module and history data based upon operation history of the battery module.

Claims

1. A battery system, comprising:

a battery module comprising a plurality of cell groups connected in series, each comprising a plurality of cells connected in series;

a plurality of integrated circuits provided to corresponding each cell group of the battery module, that perform detection of terminal voltages of the cells in the corresponding each cell group, and that also perform diagnosis; and

a battery controller that, along with issuing commands to the plurality of integrated circuits, also receives results of detection and results of diagnosis by the plurality of integrated circuits;

wherein the battery system comprises a writable non-volatile memory, and data is stored in the writable non-volatile memory specifying usage environment of the battery module, including a maximum voltage or a maximum current of the battery module and history data based upon operation history of the battery module;

at least a first storage block and a second storage block are set as a storage block for storing the data specifying the usage environment and the history data in a storage region of the non-volatile memory;

data stored in a storage block, among the first and the second storage blocks in the non-volatile memory, in which writing of data is performed later is read out; and

as a result of being decided whether or not the data that has been read out is normal, if it has been decided that the data that has been read out is normal, then, among the first and the second storage blocks, writing of next data in the non-volatile memory is performed into a storage block that is different from the storage block from which the data that it was decided was normal was read out; and

wherein, if it has been decided that the data that has been read out is anomalous, then the writing of next data to the non-volatile memory is performed to the storage block that is the same as the storage block from which the data that it was decided was anomalous was read out.

2. A battery system according to claim 1, wherein when storing, as the history data in the non-volatile memory, as stored data that is not to be deleted, data indicating the states of the cells in a state in which a cumulative value indicating operation history of the battery module satisfies a predetermined condition, this data is stored in a storage block that is set in the non-volatile memory as the data that is not to be deleted.

3. A battery system according to claim 1, wherein, as the history data, data representing states of the cells each time integrated value of current of the battery module reaches a predetermined value is appended, as stored data that is not to be deleted, to the stored data that is not to be deleted that is already stored, and is stored in the non-volatile memory.

4. A battery system according to claim 1, wherein, as the history data, data representing states of the cells each time the integrated value of the operation time of the battery module reaches a predetermined value is appended, as stored data that is not to be deleted, to the stored data that is not to be deleted that is already stored, and is stored in the non-volatile memory.

5. A battery system according to claim 1, wherein, as the history data, data representing states of the cells each time an integrated value related to the number of episodes of operation of the battery module reaches a predetermined value is appended, as stored data that is not to be deleted, to the stored data that is not to be deleted that is already stored, and is stored in the non-volatile memory.

6. A battery system according to claim 1, wherein:

a circuit is provided for making charge states (SOCs) of the cells uniform; and

data specifying operational time intervals calculated for striving to making the charge states (SOCs) of the cells uniform is appended, as stored data that is not to be deleted, to the stored data not to be deleted that is already stored, and is stored in the non-volatile memory as the history data.

7. A battery system according to claim 1, the battery system comprising a volatile memory, wherein, at start of operation, data representing the usage environment and history data stored in the non-volatile memory are read out from the non-volatile memory and are written into the volatile memory, during operation data written in the volatile memory is updated, and during ending of operation updated data stored in the volatile memory is written into the non-volatile memory for a second time.

8. A battery system according to claim 1, wherein, if it has been decided that the data that has been read out is anomalous, then new writing of data to the non-volatile memory is performed both for the first storage block and for the second storage block.

9. A battery system according to claim 1, wherein:

a third storage block is further set in the non-volatile memory; and

if it has been decided that the data that has been read out is anomalous, then, when writing next data to the non-volatile memory, the next data is written to the third storage block, and, when reading out the next data from the non-volatile memory, data stored in the third storage block is read out.

10. A battery system according to claim 1, wherein:

a third storage block is further set in the non-volatile memory; and

if it has been decided that the data that has been read out is anomalous, then, when writing next data to the non-volatile memory, the next data is written both to the storage block from which the data that it was decided was anomalous was read out and to the third storage block.

11. A battery system according to claim 7, wherein terminal voltages of the cells are detected during operation starting, variation or deviation of SOCs is obtained from the terminal voltages that have been detected during operation starting, the variation or deviation of the SOCs that has been obtained is compared with variation or deviation of the SOCs that is stored in the non-volatile memory, and it is determined that an anomaly is present if the variation or deviation of the SOCs is increased.

12. A battery system according to claim 7, wherein terminal voltages of the cells are detected during operation starting, a discharge time for making the SOCs uniform is obtained from the terminal voltages that have been detected during operation starting, the discharge time that has been obtained is compared with discharge time that is stored in the non-volatile memory, and it is determined that an anomaly is present if the discharge time is increased.

13. A battery system according to claim 7, wherein terminal voltages of the cells are detected during operation starting, the terminal voltages of the cells that have been detected are compared with the terminal voltages of the cells that are stored in the non-volatile memory, and it is determined that an anomaly is present if terminal voltage is increased.