Car power source apparatus for detecting a ground fault in a vehicle power supply

• US 8,212,385 B2
• Filed: 08/28/2009
• Issued: 07/03/2012
• Est. Priority Date: 08/29/2008
• Status: Active Grant

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Oosawa, Takeshi, Yugou, Masaki
• Primary Examiner(s): Amrany, Adi
• Application Number:
  US12/549,901
• Publication Number:
  US 20100052419A1
• Time in Patent Office: 1,040 Days
• Field of Search: 307/9.1, 307/10.1, 307/10.7
• US Class Current: 307/10.7
• 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 50/66 Arrangements of batteries
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 58/18 of two or more battery modules
• CPC Class Codes: G01R 31/007 using microprocessors or computers
• 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: G01R 31/52 Testing for short-circuits, leakage current or ground faults
• CPC Class Codes: G01R 31/69 of terminals at the end of a cable or a wire harness; of plugs; of sockets, e.g. wall sockets or power sockets in appliances
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A car power source apparatus is provided to include a driving battery 11 outputting an output voltage for driving a car, a monitoring and control circuit 21 monitoring and controlling the driving battery 11 and connected to an auxiliary battery 3 via power supply lines 2, and a battery case 1 housing the driving battery 11 and the monitoring and control circuit 21 and connected to a car chassis ground 5 via a ground line 4. Further, the power source apparatus is provided with a connection detection circuit 40. This connection detection circuit 40 determines the condition of the connection of the battery case 1 and an auxiliary battery 3 power supply line 2 via the ground line 4 and the car chassis ground 5 to determine the condition of the ground line 4 connection.

Claims

1. A car power source apparatus comprising:

a driving battery that outputs an output voltage to drive a car;

a monitoring and control circuit that monitors and controls the driving battery and is connected, via a ground line connection, to an auxiliary battery via power supply lines;

a battery case that houses the driving battery and the monitoring and control circuit and is connected to a car chassis ground via a ground line; and

a connection detection circuit that determines a condition of the ground line connection between the battery case and the car chassis ground, so as to determine whether or not the ground line connection has failed;

wherein the connection detection circuit determines the condition of the ground line connection between the battery case and the car chassis ground by detecting a condition of a connection between the battery case and one of the power supply lines connected to the auxiliary battery via the ground line and the car chassis ground.

2. The car power source apparatus as recited in claim 1,

wherein the monitoring and control circuit includes a leakage detection circuit, and

wherein a ground switch is included inside the battery case to connect the battery case with a negative-side power supply line connected to the auxiliary battery when the connection detection circuit detects that the ground line connection between the battery case and the car chassis ground has failed.

3. The car power source apparatus as recited in claim 2, wherein the leakage detection circuit detects leakage current between the driving battery and the car chassis ground to detect leakage.

4. The car power source apparatus as recited in claim 1,

wherein the connection detection circuit includes a semiconductor switching device connected between a positive-side power supply line of the power supply lines and a negative-side power supply line of the power supply line,

wherein an input-side of the semiconductor switching device is connected through a bias resistor to the positive-side power supply line and to the ground line,

wherein a bias voltage of the semiconductor switching device changes depending on whether or not the ground line is connected to the car chassis ground, and

wherein the semiconductor switching device is switched OFF or ON to determine the condition of the ground line connection between the battery case and the car chassis ground.

5. The car power source apparatus as recited in claim 4, wherein the input-side of the semiconductor switching device of the connection detection circuit is connected to the bias resistor through a diode.

6. The car power source apparatus as recited in claim 4, wherein the bias resistor is connected to the ground line through a diode.

7. The car power source apparatus as recited in claim 4, wherein the semiconductor switching device is turned OFF when the ground line connects the battery case to the car chassis ground, and is switched ON when the ground line connection between the battery case and the car chassis ground fails.

8. The car power source apparatus as recited in claim 7,

wherein the semiconductor switching device is a bipolar transistor,

wherein a load resistor is connected to a collector of the bipolar transistor,

wherein an output of the bipolar transistor is HIGH for a normal ground line connection between the battery case and the car chassis ground and LOW for a ground line connection failure between the battery case and the car chassis ground, and

wherein the condition of the ground line connection between the battery case and the car chassis ground is judged by a HIGH or a LOW output from the bipolar transistor.

9. The car power source apparatus as recited in claim 8,

wherein the connection detection circuit includes a ground switch to connect the battery case with the negative-side power supply line, when the ground line connection between the battery case and the car chassis ground fails,

wherein the ground switch is switched OFF for a HIGH output from the bipolar transistor and is switched ON for a LOW output from the bipolar transistor, and

wherein the ground switch is switched ON for a ground line connection failure to connect the battery case to the car chassis ground.

10. The car power source apparatus as recited in claim 1,

wherein the battery case includes a battery unit case housing the driving battery, a circuit board case housing circuit boards implementing the monitoring and control circuit, and an electronic component case housing the circuit board case,

wherein the circuit board case is attached to the electronic component case via first set screws,

wherein the electronic component case is attached to the battery unit case via second set screws,

wherein the first set screws electrically connect the circuit board case to the electronic component case, and

wherein the second set screws electrically connect the electronic component case to the battery unit case.

11. The car power source apparatus as recited in claim 10, wherein the ground line is connected to either the battery unit case, the circuit board case, or the electronic component case, so as to connect the battery case to the car chassis ground.

12. The car power source apparatus as recited in claim 1, wherein the monitoring and control circuit is circuitry that detects a voltage and a current of each individual battery that makes up the driving battery and controls charging and discharging of the driving battery.

13. The car power source apparatus as recited in claim 1, wherein the monitoring and control circuit is a leakage detection circuit that detects leakage of the driving battery.

14. The car power source apparatus as recited in claim 1, wherein the monitoring and control circuit is connected to the auxiliary battery via the power supply lines, and operating power is supplied from the auxiliary battery to the monitoring and control circuit by the power supply lines.