CELL CONTROL UNIT FAULT DETECTION SYSTEMS AND METHODS

• US 20170126035A1
• Filed: 08/31/2016
• Published: 05/04/2017
• Est. Priority Date: 11/04/2015
• Status: Active Grant

• Current Assignee: CPS Technology Holdings, LLC
• Original Assignee: Johnson Controls Technology Company (Johnson Controls International plc)
• Inventors: Tosch, Charles S., Dulle, Ronald J.
• Granted Patent: US 10,601,233 B2
• Time in Patent Office: Days
• CPC Class Codes: B60L 2240/54 related to batteries
• 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 50/64 Constructional details of batteries specially adapted for electric vehicles
• CPC Class Codes: B60L 50/66 Arrangements of batteries
• CPC Class Codes: B60L 58/10 for monitoring or controlling batteries
• CPC Class Codes: B60L 58/20 having different nominal voltages
• CPC Class Codes: B60L 58/21 having the same nominal voltage
• CPC Class Codes: B60L 58/24 for controlling the temperature of batteries
• CPC Class Codes: G01R 31/3835 involving only voltage measurements
• 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: G06F 1/266 Arrangements to supply power to external peripherals either directly from the computer or under computer control, e.g. supply of power through the communication port, computer controlled power-strips
• CPC Class Codes: G06F 1/3212 Monitoring battery levels, e.g. power saving mode being initiated when battery voltage goes below a certain level
• CPC Class Codes: G06F 30/13 Architectural design, e.g. computer-aided architectural design [CAAD] related to design of buildings, bridges, landscapes, production plants or roads
• CPC Class Codes: G06F 30/15 Vehicle, aircraft or watercraft design
• CPC Class Codes: H01M 10/42 Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells H01M10/60 takes precedence
• CPC Class Codes: H01M 10/4207 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/425 Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing printed circuits H05K1/00
• CPC Class Codes: H01M 10/48 Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569
• CPC Class Codes: H01M 10/482 : for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 2010/4271 : Battery management systems including electronic circuits, e.g. control of current or voltage to keep battery in healthy state, cell balancing
• CPC Class Codes: H01M 2220/20 : Batteries in motive systems, e.g. vehicle, ship, plane
• CPC Class Codes: H01M 50/249 : specially adapted for aircraft or vehicles, e.g. cars or trains constructional details of batteries specially adapted for electric vehicles B60L50/64
• CPC Class Codes: H01M 50/574 : Devices or arrangements for the interruption of current
• CPC Class Codes: H02J 2310/48 : for electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: H02J 7/0031 : using battery or load disconnect circuits H02J9/002 takes precedence
• CPC Class Codes: H04L 67/12 : specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks
• CPC Class Codes: Y02T 10/70 : Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 90/14 : Plug-in electric vehicles
• CPC Class Codes: Y02T 90/16 : Information or communication technologies improving the operation of electric vehicles

Abstract

One embodiment of the present disclosure describes a battery system including a battery module with a first and second cell group connected in series; and a cell control unit communicatively coupled to a plurality of sensors, in which the cell control unit includes a first analog-to-digital converter that outputs a first cell group voltage; a second analog-to-digital converter that output a second cell group voltage; outputs a measured battery module voltage; and logic circuitry that determines a calculated battery module voltage based at least in part on the first cell group voltage and the second cell group voltage; and determines whether a fault is expected to be present in the cell control unit, the battery module, or both based at least in part on the measured battery module voltage and the calculated battery module voltage.

Claims

1. A battery system comprising:

a battery module comprising a first cell group and a second cell group connected in series between terminals of the battery module, wherein the first cell group comprises a first plurality of battery cells connected in series and the second cell group comprises a second plurality of battery cells connected in series; and

a cell control unit communicatively coupled to a plurality of sensors, wherein the cell control unit comprises;

a first analog-to-digital converter configured to output a first cell group voltage based at least in part on a first voltage measured across the first cell group by the plurality of sensors;

a second analog-to-digital converter configured to;

output a second cell group voltage based at least in part on a second voltage measured across the second cell group by the plurality of sensors;

output a measured battery module voltage based at least in part on a third voltage measured across the battery module by the plurality of sensors; and

logic circuitry communicatively coupled to the first analog-to-digital converter and the second analog-to-digital converter, wherein the logic circuitry is configured to;

determine a calculated battery module voltage based at least in part on the first cell group voltage and the second cell group voltage; and

determine whether a fault is expected to be present in the cell control unit, the battery module, or both based at least in part on the measured battery module voltage and the calculated battery module voltage.

2. The battery system of claim 1, wherein the logic circuitry comprises:

arithmetic circuitry configured to;

determine the calculated battery module voltage by summing the first cell group voltage and the second cell group voltage; and

determine a voltage difference between the calculated battery module voltage and the measured battery module voltage; and

comparison circuitry configured to determine that the fault is expected to be present when the voltage difference is greater than a difference threshold.

3. The battery system of claim 2, wherein the difference threshold varies based at least in part on the measured battery module voltage.

4. The battery system of claim 2, wherein the logic circuitry is configured to determine the difference threshold as a percentage of the measured battery module voltage.

5. The battery system of claim 1, wherein the cell control unit comprises:

a first sensor communication interface communicatively coupled to the first analog-to-digital converter and a first sensor of the plurality of sensors, wherein the first sensor communication interface is configured to;

receive a first analog representation of the first voltage measured by the first sensor; and

communicate the first analog representation to the first analog-to-digital converter; and

a second sensor communication interface communicatively coupled to the second analog-to-digital converter, a second sensor of the plurality of sensors, and a third sensor of the plurality of sensors, wherein the second sensor communication interface is configured to;

receive a second analog representation of the second voltage measured by the second sensor;

receive a third analog representation of the third voltage measured by the third sensor; and

communicate the second analog representation and the third analog representation to the second analog-to-digital converter.

6. The battery system of claim 1, comprising a string control unit configured to control operation of a battery string comprising the battery module, wherein:

the cell control unit is configured to indicate the fault when the cell control unit detects that the fault is expected to be present; and

the string control unit is configured to instruct a relay to disconnect the battery string electrically from the battery system based at least in part on indication of the fault received from the cell control unit.

7. The battery system of claim 1, wherein the logic circuitry is configured to:

determine that the fault is present in the battery module when the first cell group voltage, the second cell group voltage, the measured battery module voltage, or any combination thereof is outside a target operating voltage; and

determine that the fault is present in the cell control unit when the calculated battery module voltage and the measured battery module voltage vary by more than a threshold.

8. The battery system of claim 1, wherein:

the logic circuitry comprises circuit connections formed during manufacture of the logic circuitry; and

the logic circuitry is configured to perform a logic operation, an arithmetic operation, or both based at least in part on the circuit connections.

9. The battery system of claim 1, wherein:

the logic circuitry comprises an application-specific integrated circuit; and

the cell control unit does not include a microprocessor.

10. The battery system of claim 1, wherein:

the battery module comprises sixteen battery cells;

the first cell group comprises a first eight battery cells in the battery module; and

the second cell group comprises a second eight battery cell in the battery module.

11. The battery system of claim 1, wherein:

the first cell group voltage comprises a first digital representation of the first voltage measured by the plurality of sensors;

the first cell group voltage comprises a second digital representation of the second voltage measured by the plurality of sensors; and

the measured battery module voltage comprises a third digital representation of the third voltage measured by the plurality of sensors.

12. A method for operating a battery control system that controls operation of a battery system, comprising:

determining, using a cell control unit in the battery control system, a first cell group voltage based at least in part on first sensor data received from a first sensor that measures voltage of a first cell group, wherein the first cell group comprises a first plurality of battery cells connected in series in a battery module of the battery system;

determining, using the cell control unit, a second cell group voltage based at least in part on second sensor data received from a second sensor that measures voltage of a second cell group, wherein the second cell group comprises a second plurality of battery cells connected in series in the battery module;

determining, using the cell control unit, a measured battery module voltage based at least in part on third sensor data received from a third sensor that measures voltage of the battery module;

determining, using the cell control unit, a calculated battery module voltage based at least in part on the first cell group voltage and the second cell group voltage;

determining, using the cell control unit, a voltage difference between the measured battery module voltage and the calculated battery module voltage; and

indicating, using the cell control unit, that a first fault is expected to be present in the cell control unit when the voltage difference is greater than a difference threshold to enable the battery control system to adjust operation of the battery system accordingly.

13. The method of claim 12, wherein:

determining the first cell group voltage comprises;

receiving the first sensor data from the first sensor, wherein the first sensor data comprises a first analog representation of a first voltage measured across the first cell group; and

generating the first cell group voltage based at least in part on the first analog representation, wherein the first cell group voltage comprises a first digital representation of the first voltage measured across the first cell group;

determining the second cell group voltage comprises;

receiving the second sensor data from the second sensor, wherein the second sensor data comprises a second analog representation of a second voltage measured across the second cell group; and

generating the second cell group voltage based at least in part on the second analog representation, wherein the second cell group voltage comprises a second digital representation of the second voltage measured across the second cell group; and

determining the measured battery module voltage comprises;

receiving the third sensor data from the third sensor, wherein the third sensor data comprises a third analog representation of a third voltage measured across terminals of the battery module; and

generating the measured battery module voltage based at least in part on the third analog representation, wherein the measured battery module voltage comprises a third digital representation of the third voltage measured across the terminals of the battery module.

14. The method of claim 12, comprising determining, using the cell control unit, whether the first fault is expected to be present by comparing the voltage difference and the difference threshold using circuit connections formed in logic circuitry of the cell control unit. wherein:

determining the calculated battery module voltage comprises summing the first cell group voltage and the second cell group voltage using the circuit connections formed in the logic circuitry;

determining the voltage difference between the measured battery module voltage and the calculated battery module voltage comprises subtracting the measured battery module voltage from the calculated battery module voltage using the circuit connections formed in the logic circuitry; and

indicating that the first fault is expected to be present when the cell control unit determines that the first fault is expected to be present using the circuit connections formed in the logic circuitry.

15. The method of claim 12, comprising determining, using the cell control unit, whether the first fault is expected to be present by comparing the voltage different and the difference threshold without the cell control unit executing instructions stored in a tangible, non-transitory, computer-readable medium, wherein:

determining the calculated battery module voltage comprises summing the first cell group voltage and the second cell group voltage without the cell control unit executing instructions stored in a tangible, non-transitory, computer-readable medium;

determining the voltage difference between the measured battery module voltage and the calculated battery module voltage comprises subtracting the measured battery module voltage from the calculated battery module voltage without the cell control unit executing instructions stored in the tangible, non-transitory, computer-readable medium; and

indicating that the first fault is expected to be present when the cell control unit determines that the first fault is expected to be present without the cell control unit executing instructions stored in the tangible, non-transitory, computer-readable medium.

16. The method of claim 12, wherein indicating that the first fault is expected to be present in the cell control unit comprises indicating that the first fault is expected to be present in the cell control unit to a string control unit communicatively coupled to the cell control unit via a serial communication bus to enable the string control unit to instruct a relay to disconnect the battery module electrically from the battery system.

17. The method of claim 12, comprising determining, using the cell control unit, the difference threshold based at least in part on the measured battery module voltage.

18. The method of claim 12, comprising determining, using the cell control unit, that a second fault is expected to be present in the battery module when the first cell group voltage varies from a first target operating voltage, the second cell group voltage varies from a second target operating voltage, the measured battery module voltage varies from a third target operating voltage, or any combination thereof.

19. A tangible, non-transitory, computer-readable medium that stores instructions executable by one or more processors of a battery control system to control operation of a battery system, wherein the instructions comprise instructions to:

instruct, using the one or more processors, a first cell control unit in the battery control system to determine whether a first fault is expected to be present in the first cell control unit based at least in part on a first cell group voltage, a second cell group voltage, a first measured battery module voltage, and a first calculated battery module voltage determined by summing the first cell group voltage and the second cell group voltage;

receive, using the one or more processors, a first indication from the first cell control unit of whether the first fault is expected to be present via a serial communication network;

instruct, using the one or more processors, a second cell control unit in the battery control system to determine whether a second fault is expected to be present in the second cell control unit based at least in part on a third cell group voltage, a fourth cell group voltage, a second measured battery module voltage, and a second calculated battery module voltage determined by summing the third cell group voltage and the fourth cell group voltage;

receive, using the one or more processors, a second indication from the second cell control unit of whether the second fault is expected to be present via the serial communication network; and

instruct, using the one or more processors, a relay to disconnect a first battery module corresponding to the first measured battery module voltage, a second battery module corresponding to the second measured battery module voltage, or both based at least in part on the first indication and the second indication.

20. The computer-readable medium of claim 19, comprising instructions to indicate, using the one or more processors, a difference threshold to the first cell control unit to enable the first cell control unit to:

determine a voltage difference between the first measured battery module voltage and the first calculated battery module voltage using only circuit connections formed in logic circuitry of the first cell control unit; and

determine whether the first fault is expected to be present by comparing the voltage difference and the difference threshold using only circuit connections formed in the logic circuitry.

21. The computer-readable medium of claim 19, wherein the instructions to instruct the relay to disconnect comprise instructions to:

instruct the relay to remain closed to maintain the first battery module and the second battery module connected in series to the battery system when the first indication received from the first cell control unit indicates that the first fault is not expected to be present and the second indication indicates that the second fault is not expected to be present; and

instruct the relay to open to disconnect the first battery module and the second battery module from the battery system when the first indication indicates that the first fault is expected to be present, the second indication indicates that the second fault is expected to be present, or both.