BATTERY SYSTEM MONITORING DEVICE

• US 20140225622A1
• Filed: 09/08/2011
• Published: 08/14/2014
• Est. Priority Date: 09/08/2011
• Status: Active Grant

• Current Assignee: Hitachi Astemo Ltd. (Hitachi, Ltd.)
• Original Assignee: Hitachi Vehicle Energy, Ltd. (Hitachi, Ltd.)
• Inventors: Kudo, Akihiko, Kikuchi, Mutsumi, Yamauchi, Tatsumi, Machida, Akihiro, Kanai, Tomonori
• Granted Patent: US 9,746,525 B2
• Time in Patent Office: Days
• US Class Current: 324/433
• CPC Class Codes: B60L 2200/26 Rail vehicles
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/36 Temperature of vehicle components or parts
• 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 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 3/0069 relating to the isolation, e.g. ground fault or leak current
• 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 50/66 Arrangements of batteries
• CPC Class Codes: B60L 58/13 Maintaining the SoC within a determined range
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: B60L 58/18 of two or more battery modules
• CPC Class Codes: B60L 58/20 having different nominal voltages
• CPC Class Codes: B60L 58/22 Balancing the charge of battery modules
• CPC Class Codes: B60L 58/24 for controlling the temperature of batteries
• CPC Class Codes: B60L 7/14 for vehicles propelled by ac motors
• CPC Class Codes: G01R 31/3842 combining voltage and current 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: H01M 10/482 : for several batteries or cells simultaneously or sequentially
• CPC Class Codes: H01M 10/486 : for measuring temperature
• 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: H02J 2310/48 : for electric vehicles [EV] or hybrid vehicles [HEV]
• CPC Class Codes: H02J 7/0016 : using shunting, discharge or bypass circuits
• CPC Class Codes: Y02E 60/10 : Energy storage using batteries
• 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 90/12 : Electric charging stations
• 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

A battery system monitoring device that monitors a battery system provided with a cell group having a plurality of battery cells connected in series with each other, including: a first control device that monitors and controls states of the plurality of battery cells of the cell group; a second control device that controls the first control device; a temperature detection unit that measures a temperature in the vicinity of the first control device; and a plurality of voltage detection lines, for measuring an inter-terminal voltage of the battery cell, which connect each of a positive electrode and a negative electrode of the battery cell and the first control device. The first control device includes a balancing switch, which performs balancing discharge of the battery cell for each of the battery cells.

Claims

1. (canceled)

2. A battery system monitoring device that monitors a battery system provided with a cell group having a plurality of battery cells connected in series w each other, comprising:

a first control device that monitors and controls states of the plurality of battery cells of the cell group;

a second control device that controls the first control device;

a temperature detection unit that measures a temperature in the vicinity of the first control device; and

a plurality of voltage detection lines, for measuring an inter-terminal voltage of the battery cell, which connect each of a positive electrode and a negative electrode of the battery cell and the first control device,

wherein the first control device includes a balancing switch, connected between the voltage detection line connected to the positive electrode of the battery cell and the voltage detection line connected to the negative electrode, which performs balancing discharge of the battery cell for each of the battery cells,

a first resistor is provided in series with the voltage detection line,

a balancing discharge circuit constituted by the balancing switch and a second resistor connected in series to the balancing switch is connected between the voltage detection line connected to the positive electrode of the battery cell and the voltage detection line connected to the negative electrode, and

a connection point between the balancing discharge circuit and the voltage detection line connected to the positive electrode of the battery cell and a connection point between the balancing discharge circuit and the voltage detection line connected to the negative electrode of the battery cell are provided at the cell group side rather than the first resistor, and

wherein the first control device further includes;

a selection unit that selects a voltage detection line connected to each of a positive electrode and a negative electrode of one battery cell or a temperature detection line connected to the temperature detection unit, and outputs a positive electrode potential and a negative electrode potential of the one battery cell or an output voltage of the temperature detection unit; and

a voltage measurement unit that measures an inter-terminal voltage of the one battery cell or the output voltage of the temperature detection unit, from the positive electrode potential and the negative electrode potential of the one battery cell which are output from the selection unit or the output voltage of the temperature detection unit, and

the second control device includes a storage unit that stores data for converting the output voltage of the temperature detection unit into a temperature.

3. The battery system monitoring device according to claim 2, wherein when the temperature in the vicinity of the first control device is equal to or less than a predetermined lower limit or equal to or greater than a predetermined upper limit during start-up of a vehicle having the battery system monitoring device mounted thereto,

the second control device controls the first control device to perform balancing discharge on a battery cell targeted for balancing discharge during previous stop of the vehicle.

4. The battery system monitoring device according to claim 2, wherein when the temperature in the vicinity of the first control device is greater than a predetermined lower limit and is smaller than a predetermined upper limit during start-up of a vehicle having the battery system monitoring device mounted thereto,

the second control device measures an inter-terminal voltage of each of the plurality of battery cells of the cell group in a state where a load that drives the vehicle is not connected to the battery system, calculates remaining capacity (SOC) of each of the plurality of battery cells, and performs balancing discharge on the basis of the SOC.

5. The battery system monitoring device according to claim 4, wherein when all the measured inter-terminal voltages of the plurality of battery cells fall within a predetermined voltage range,

the second control device calculates an SOC of each of the plurality of battery cells and a deviation thereof, and controls the first control device to perform balancing discharge of a battery cell having an SOC with a deviation equal to or more than a predetermined threshold.

6. The battery system monitoring device according to claim 4, wherein when the measured inter-terminal voltages of the plurality of battery cells do not fall within a predetermined voltage range at all, and a predetermined time elapses from a point of time at which a previous SOC is calculated using an OCV,

the second control device calculates an SOC of each of the plurality of battery cells and a deviation thereof, and controls the first control device to perform balancing discharge of a battery cell having an SOC with a deviation equal to or more than a predetermined threshold.

7. The battery system monitoring device according to claim 4, wherein when the measured inter-terminal voltages of the plurality of battery cells do not fall within a predetermined voltage range at all,

the second control device controls the first control device to perform balancing discharge of a battery cell targeted for balancing discharge during previous stop of the vehicle.

8. The battery system monitoring device according to claim 4, further comprising a current detection unit that detects a charge and discharge current of the battery system,

wherein when the measured inter-terminal voltages of the plurality of battery cells do not fall within a predetermined voltage range at all,

the second control device controls the first control device to perform balancing discharge of a battery cell targeted for balancing discharge during previous stop of the vehicle, and

the SOC of each of the plurality of battery cells is calculated by integrating the charge and discharge current of the battery system detected by the current detection unit and a current of balancing discharge of the battery cell, to the SOC during previous stop of the vehicle.

9. The battery system monitoring device according to claim 3, wherein the second control device performs the balancing discharge of the battery cell targeted for the balancing discharge, with priority given to a battery cell having a large deviation for the SOC.

10. The battery system monitoring device according to claim 8, wherein the second control device performs the balancing discharge of the battery cell targeted for the balancing discharge, with priority given to a battery cell having a large deviation for the SOC.

11. The battery system monitoring device according to claim 3, wherein the second control device controls a duty of a balancing switch corresponding to the battery cell targeted for the balancing discharge to perform the balancing discharge of the battery cell targeted for the balancing discharge so that the temperature in the vicinity of the first control device is less than the predetermined upper limit.

12. The battery system monitoring device according to claim 2, further comprising:

N (N≧

1) cell groups connected in series with each other;

M (M≧

1) first control devices that control the N cell groups; and

the second control device which is a high-order control device of the M first control devices,

a highest-order first control device of the M first control devices and the second control device are connected to each other by the communication line through an insulating element,

a lowest-order first control device of the M first control devices and the second control device are connected to each other by the communication line through an insulating element,

the M first control devices are connected to each other through the communication line, and

the M first control devices are controlled by a control signal and control data from the second control device.

15. The battery system monitoring device according to claim 7, wherein the second control device performs the balancing discharge of the battery cell targeted for the balancing discharge, with priority given to a battery cell having a large deviation for the SOC.

16. The battery system monitoring device according to claim 7, wherein the second control device controls a duty of a balancing switch corresponding to the battery cell targeted for the balancing discharge to perform the balancing discharge of the battery cell targeted for the balancing discharge so that the temperature in the vicinity of the first control device is less than the predetermined upper limit.

17. The battery system monitoring device according to claim 9, wherein the second control device controls a duty of a balancing switch corresponding to the battery cell targeted for the balancing discharge to perform the balancing discharge of the battery cell targeted for the balancing discharge so that the temperature in the vicinity of the first control device is less than the predetermined upper limit.

13. A battery system monitoring device that monitors a battery system provided with a cell group having a plurality of battery cells connected in series with each other, in which regarding OCV-SOC characteristics, the plurality of single cells having characteristics where a change in the OCV caused by a change in the SOC is small in a range of a predetermined OCV, and a change in the OCV caused by a change in the SOC is large in a range other than the predetermined OCV, the battery system monitoring device comprising:

a current detection unit that detects a charge and discharge current of the battery system;

a first control device that monitors and controls states of the plurality of battery cells of the cell group;

a second control device that controls the first control device;

a voltage detection circuit that detects a voltage of the battery cell;

a temperature detection unit that measures a temperature in the vicinity of the voltage detection circuit; and

a balancing discharge circuit that performs balancing discharge control of reducing a variation in the SOC of the plurality of battery cells,

wherein when the temperature of the voltage detection circuit detected by the temperature detection unit is in a predetermined temperature range,

the SOC of each battery cell is calculated by a first SOC calculation method of calculating the SOC of each battery cell, on the basis of the OCV of the plurality of battery cells detected by the voltage detection circuit, and

when the temperature of the voltage detection circuit detected by the temperature detection unit is out of the predetermined temperature range,

the SOC of each battery cell is calculated by a second SOC calculation method of calculating the SOC of each battery cell by integrating the charge and discharge current of the battery system detected by the current detection unit and a balancing discharge current of each of the plurality of battery cells caused by the balancing discharge circuit.

14. The battery system monitoring device according to claim 13, wherein when the temperature of the voltage detection circuit detected by the temperature detection unit is in the predetermined temperature range,

the SOC of each battery cell is calculated by the first SOC calculation method, and first balancing discharge control in which an amount of heat generation of the balancing discharge circuit is suppressed is performed, and

when the temperature of the voltage detection circuit detected by the temperature detection unit is out of the predetermined temperature range,

the SOC of each battery cell is calculated by the second SOC calculation method, and second balancing discharge control in which the amount of heat generation of the balancing discharge circuit is not suppressed is performed.