Vehicle power supply device

• US 20090091332A1
• Filed: 09/25/2008
• Published: 04/09/2009
• Est. Priority Date: 09/28/2007
• Status: Active Grant

• Current Assignee: Hitachi Automotive Systems Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi, Ltd., Hitachi Vehicle Energy, Ltd.
• Inventors: Sakabe, Kei, Emori, Akihiko, Kikuchi, Mutsumi, Kudo, Akihiko, Kawahara, Youhei, Yamauchi, Tatsumi, Kubo, Kenji
• Granted Patent: US 8,212,571 B2
• Time in Patent Office: Days
• US Class Current: 324/537
• CPC Class Codes: B60L 50/64 Constructional details of batteries specially adapted for electric vehicles
• CPC Class Codes: B60L 58/19 Switching between serial connection and parallel connection of battery modules
• CPC Class Codes: B60L 58/21 having the same nominal voltage
• CPC Class Codes: H02J 7/0018 using separate charge circuits
• CPC Class Codes: H02J 7/0019 using switched or multiplexed charge circuits
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A vehicle power supply device comprises a lithium battery module that includes a plurality of lithium battery cells, first control devices, voltage detection harnesses via which terminal voltages at individual lithium battery cells are input to the first control devices, a second control device and a signal transmission path through which signals are transmitted. The first control device comprises a selection circuit that selects terminal voltages at individual lithium battery cells, a voltage measurement circuit that measures the selected terminal voltages, balancing switches used to discharge individual lithium battery cells, a balancing switch control circuit that controls open/close of the balancing switches, and a diagnosis circuit for detecting an electrically abnormal connection in the detection harnesses.

Claims

1. A vehicle power supply device, comprising:

a lithium battery module that is constituted with a plurality of serially connected lithium battery groups each include a plurality of serially connected lithium battery cells;

a plurality of first control devices each disposed in correspondence to the plurality of lithium battery cell groups;

a plurality of voltage detection harnesses via which terminal voltages at individual lithium battery cells are input from the corresponding lithium battery cell group to the plurality of first control devices;

a second control device that controls all of the plurality of lithium battery cells; and

a signal transmission path through which signals are transmitted between the plurality of first control devices and the second control device, wherein;

each of the plurality of first control devices is an integrated circuit; and

each of the plurality of integrated circuits comprises;

a selection circuit that selects in a predetermined order terminal voltages at individual lithium battery cells that are input from the corresponding lithium battery group via the voltage detection harnesses;

a voltage measurement circuit that measures the selected terminal voltages;

a plurality of balancing switches used to discharge individual lithium battery cells of the corresponding lithium battery group;

a balancing switch control circuit that controls open/close of the balancing switches; and

a diagnosis circuit for detecting an electrically abnormal connection in the detection harnesses, and wherein;

the plurality of integrated circuits individually execute cyclically a measurement of terminal voltages at individual lithium battery cells in the corresponding lithium battery group and an abnormality diagnosis for electrical connections in detection harnesses used to input the terminal voltages, transmit the measurement result of the terminal voltages to the second control device through the signal transmission path, and, if the abnormality diagnosis result indicates an abnormality, transmit a signal indicating an abnormality to the second control device through the signal transmission path.

2. A vehicle power supply device according to claim 1, wherein:

the balancing switch control circuit controls open/close of the balancing switches so as to give priority to an execution of a diagnosis for detecting an electrically abnormal connection in the detection harnesses over a discharge instruction sent from the second control device.

3. A vehicle power supply device according to claim 1, wherein:

the balancing switch control circuit and the diagnosis circuit execute necessary operations for a diagnosis for detecting an electrically abnormal connection in the detection harnesses based upon a diagnosis instruction sent from the second control device.

4. A vehicle power supply device, comprising:

a lithium battery module that is constituted with a plurality of serially connected lithium battery groups each include a plurality of serially connected lithium battery cells;

a plurality of first control devices each disposed in correspondence to the plurality of lithium battery cell groups;

a plurality of voltage detection harnesses via which terminal voltages at individual lithium battery cells are input from the corresponding lithium battery cell group to the plurality of first control devices;

a second control device that controls all of the plurality of lithium battery cells; and

a signal transmission path through which signals are transmitted between the plurality of first control devices and the second control device, wherein;

each of the plurality of first control devices is an integrated circuit; and

each of the plurality of integrated circuits comprises;

a selection circuit that selects in a predetermined order terminal voltages at individual lithium battery cells that are input from the corresponding lithium battery group via the voltage detection harnesses;

a voltage measurement circuit that measures the selected terminal voltages;

a plurality of balancing switches used to discharge individual lithium battery cells of the corresponding lithium battery group;

a balancing switch control circuit that controls open/close of the balancing switches; and

a diagnosis circuit for detecting an electrically abnormal connection in the detection harnesses, and wherein;

the balancing switch control circuit controls open/close of the balancing switches based upon a discharge instruction sent from the second control device via the signal transmission path, and controls open/close of the balancing switches upon detecting an electrically abnormal connection in the detection harnesses; and

the diagnosis circuit detects the electrically abnormal connection in the detection harnesses in synchronization with open/close control via the balancing switches.

5. A vehicle power supply device according to claim 4, wherein:

the balancing switch control circuit controls open/close of the balancing switches so as to give priority to an execution of a diagnosis for detecting an electrically abnormal connection in the detection harnesses over a discharge instruction sent from the second control device.

6. A vehicle power supply device according to claim 4, wherein:

the balancing switch control circuit and the diagnosis circuit execute necessary operations for a diagnosis for detecting an electrically abnormal connection in the detection harnesses based upon a diagnosis instruction sent from the second control device.

7. A vehicle power supply device, comprising:

a plurality of serially connected lithium battery cells;

a measurement circuit that measures terminal voltages at the individual battery cells;

a plurality of detection harnesses that connect the measurement circuit with terminals of the individual battery cells;

a plurality of series circuits including resistors and balancing switches with which discharge current for the battery cells flows;

a control circuit that controls the balancing switches; and

a diagnosis circuit that includes a comparator circuit, wherein;

the individual series circuits are connected in parallel to the individual battery cells via the detection harnesses;

the balancing switches are switched into the continuous state by the control circuit;

terminal voltages at battery cells which are supplied via the detection harnesses are measured by the measurement circuit;

a predetermined threshold is compared with measured terminal voltages by the comparator circuit; and

thus an abnormal state is judged by the diagnosis circuit.

8. A vehicle power supply device according to claim 7, wherein:

the measurement circuit comprises;

a selection circuit that selects in a predetermined order a terminal voltage from terminal voltages at a plurality of battery cells which are supplied via the detection harnesses; and

an analog/digital converter that converts the selected terminal voltage to a digital value, and wherein;

an abnormality diagnosis is executed by comparing a digitized terminal voltage at the battery cell with the threshold.

9. A vehicle power supply device, wherein:

a plurality of groups including a plurality of serially connected lithium battery cells are serially connected;

a plurality of integrated circuits for detecting terminal voltages at lithium battery cells in each group are individually correlated to each of the groups and thus provided;

a plurality of detection harnesses via which terminal voltages at a plurality of lithium battery cells in groups correlated to the individual integrated circuits are supplied are provided;

the integrated circuits each include a selection circuit and a voltage measurement circuit for measuring selectively and sequentially terminal voltages at a plurality of lithium battery cells which have been supplied via the detection harnesses;

the integrated circuits each further include a balancing switch for flowing discharge current for a plurality of lithium battery cells in a correlated group, a control circuit that controls open/close of the balancing switch, and a diagnosis circuit;

the control circuit of each of the integrated circuits closes the balancing switch of a measurement target lithium battery cell and opens the balancing switch of a next measurement target lithium battery cell; and

the voltage measurement circuit of each of the integrated circuits measures a terminal voltage at a measurement target lithium battery cell during a period that the balancing switch remains opened, and diagnoses an abnormality via the diagnosis circuit.

10. A vehicle power supply device according to claim 9, wherein:

the integrated circuits each include a stage signal generating circuit that performs in a predetermined order a selection of the balancing switch with which the open/close control is performed and a selection of a terminal voltage at a measurement target lithium battery cell from among a plurality of supplied terminal voltages at lithium battery cells.

11. A vehicle power supply device according to claim 10, wherein:

one of the two adjacent integrated circuits supplies a synchronous signal to the other integrated circuit in synchronization with a particular stage of the predetermined order; and

the other integrated circuit executes a switching operation for the other integrated circuit in a predetermined order based upon the synchronous signal.