Automotive power supply system

• US 8,159,184 B2
• Filed: 08/19/2008
• Issued: 04/17/2012
• 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. (Hitachi, Ltd.)
• Inventors: Emori, Akihiko, Kawahara, Youhei, Sakabe, Kei, Kikuchi, Mutsumi, Yamauchi, Tatsumi, Kudo, Akihiko
• Primary Examiner(s): Phan, Huy Q
• Assistant Examiner(s): LE, SON T
• Application Number:
  US12/194,354
• Publication Number:
  US 20090085516A1
• Time in Patent Office: 1,337 Days
• Field of Search: 320113-118, 320/162, 320/164, 320/133
• US Class Current: 320/116
• 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 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 58/14 Preventing excessive discharging
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: B60L 58/22 Balancing the charge of battery modules
• CPC Class Codes: B60L 58/26 by cooling
• CPC Class Codes: G01R 31/392 Determining battery ageing or deterioration, e.g. state of health
• 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: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/0014 Circuits for equalisation of charge between batteries
• CPC Class Codes: H02J 7/0025 Sequential battery discharge in systems with a plurality of batteries
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]
• CPC Class Codes: H02J 7/005 Detection of state of health [SOH]
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

An automotive power supply system comprises a battery module that includes serially connected battery groups each constituted with serially connected battery cells, integrated circuits each disposed in correspondence to one of the battery groups, a control circuit, a transmission path through which the integrated circuits are connected to the control circuit and a relay circuit via which an electrical current is supplied from the battery module. In response to a start signal instructing an operation start and received via the transmission path, each integrated circuit measures terminal voltages at the individual battery cells in the corresponding battery group and executes an abnormality diagnosis. If abnormality diagnosis results provided by the integrated circuits indicate no abnormality, the control circuit closes the relay, enabling supply of electrical current from the battery module and subsequently, the control circuit receives measurement results from the integrated circuits via the transmission path.

Claims

1. A power supply system comprising:

a battery module that includes a plurality of serially connected battery groups each constituted with a plurality of serially connected battery cells;

a plurality of integrated circuits each disposed in correspondence to one of the battery groups;

a control circuit;

a transmission path through which the integrated circuits are connected to the control circuit; and

a relay circuit via which an electrical current is supplied from the battery module, wherein;

in response to a start signal instructing an operation start and received via the transmission path, each integrated circuit measures terminal voltages at the battery cells in the corresponding battery group and executes an abnormality diagnosis; and

if abnormality diagnosis results provided by the integrated circuits indicate no abnormality, the control circuit closes the relay, enabling supply of electrical current from the battery module and subsequently, the control circuit receives measurement results from the integrated circuits via the transmission path.

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

the integrated circuit cyclically generates a selection signal to be used to measure the battery cells constituting the corresponding battery group in a predetermined order; and

the integrated circuit includes a selection circuit that selects a terminal voltage to be measured based upon the selection signal, an analog/digital converter that converts the selected terminal voltage to a digital value and a digital comparator circuit that executes an abnormal state diagnosis based upon the digital value resulting from conversion executed at the analog/digital converter, and transmits a signal indicating an abnormality to the control circuit if diagnosis results indicate an abnormal state.

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

the control circuit transmits the start signal to each integrated circuit upon receiving a signal generated based upon an operation of a key switch at a vehicle.

4. A power supply system according to claim 1, wherein:

the integrated circuit includes a one-bit signal transmission/reception circuit and a serial signal transmission/reception circuit and transmits a signal indicating an abnormality from the one-bit signal transmission circuit upon detecting an abnormality.

5. A power supply system comprising:

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

a plurality of integrated circuits each disposed in correspondence to one of the lithium battery groups in the battery module;

a transmission path through which the integrated circuits are connected; and

a relay via which power is supplied from the lithium battery module, wherein;

the integrated circuit cyclically generates a stage signal to be used to specify a measurement target lithium battery cell in response to an operation start signal; and

the integrated circuit includes;

a selection circuit that selects the measurement target lithium battery cell in the lithium battery group corresponding to the integrated circuit based upon the stage signal;

an analog/digital converter that converts a terminal voltage at the lithium battery having been selected by the selection circuit to a digital value;

a digital comparator circuit that compares the digitized terminal voltage value with an over-charge diagnosis threshold value; and

a transmission circuit that outputs an abnormality signal indicating an abnormality based upon comparison results provided from the digital comparator circuit and includes a one-bit signal transmission terminal used to transmit the abnormality signal, a one-bit signal reception terminal, a serial transmission terminal and a serial reception terminal.