Car power source apparatus

• US 20090079434A1
• Filed: 09/19/2008
• Published: 03/26/2009
• Est. Priority Date: 09/26/2007
• Status: Active Grant

• Current Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Sanyo Electric Company Limited (Panasonic Holdings Corporation)
• Inventors: Iwasaki, Ryuta, Osawa, Takeshi
• Granted Patent: US 8,134,335 B2
• Time in Patent Office: Days
• US Class Current: 324/434
• CPC Class Codes: G01R 31/007 using microprocessors or computers
• CPC Class Codes: G01R 31/382 Arrangements for monitoring battery or accumulator variables, e.g. SoC
• 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: 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 10/482 for several batteries or cells simultaneously or sequentially
• CPC Class Codes: Y02E 60/10 Energy storage using batteries

Abstract

The car power source apparatus is provided with a leakage detection circuit 3 having a battery 1 with a plurality of battery units 2 connected in series, a first series circuit 11 made up of first leakage detection resistors 12 and a first leakage detection switch 13 to connect the first connection node 10 of the series connected battery units 2 to ground 9, a second series circuit 21 made up of second leakage detection resistors 22 and a second leakage detection switch 23 to connect the second connection node 20 of the series connected battery units 2 to ground 9, and voltage detection circuits 4 to detect voltage of the first leakage detection resistors 12 and the second leakage detection resistors 22. Further, the car power source apparatus is provided with a failure detection circuit 5 to control the first leakage detection switch 13 and the second leakage detection switch 23 ON and OFF and determine failure of the leakage detection circuit 3 from voltages detected by the voltage detection circuits 4.

Claims

1. A car power source apparatus provided with a leakage detection circuit comprising:

a battery having a plurality of battery units connected in series;

a first series circuit made up of first leakage detection resistors and a first leakage detection switch to connect the first connection node of the series connected battery units to ground;

a second series circuit made up of second leakage detection resistors and a second leakage detection switch to connect the second connection node of the battery units to ground;

voltage detection circuits to detect voltage of the first leakage detection resistors and the second leakage detection resistors; and

characterized in that the car power source apparatus is provided with a failure detection circuit to control the first leakage detection switch and the second leakage detection switch ON and OFF and determine failure of the leakage detection circuit from voltages detected by the voltage detection circuits.

2. The car power source apparatus as recited in claim 1 wherein the failure detection circuit determines failure of the leakage detection circuit from the ratio of voltages of the first leakage detection resistors and the second leakage detection resistors while switching the first leakage detection switch and the second leakage detection switch ON and OFF.

3. The car power source apparatus as recited in claim 1 wherein the first leakage detection resistors and the second leakage detection resistors have the same electrical resistance.

4. The car power source apparatus as recited in claim 1 wherein the first leakage detection resistors and the second leakage detection resistors are a series connection of a plurality of detection resistors.

5. The car power source apparatus as recited in claim 1 wherein the electrical resistance of the first leakage detection resistors and the second leakage detection resistors is several MΩ

.

6. The car power source apparatus as recited in claim 1 wherein the voltage detection circuits detect voltage with respect to an intermediate node between the first connection node and the second connection node connected to the first series circuit and second series circuit.

7. The car power source apparatus as recited in claim 6 wherein the intermediate node is specified to make the voltage between the first connection node connected to the first series circuit and the intermediate node equal to the voltage between the second connection node connected to the second series circuit and the intermediate node.

8. The car power source apparatus as recited in claim 1, wherein the car power source apparatus has two voltage detection circuits, which are the voltage detection circuit to detect the voltage of the first leakage detection resistors and the voltage detection circuit to detect the voltage of the second leakage detection resistors.

9. The car power source apparatus as recited in claim 1 wherein the failure detection circuit turns the first leakage detection switch and the second leakage detection switch OFF in a first step, a first voltage for the first leakage detection resistors, and a second voltage, for the second leakage detection resistors are detected, and a first voltage ratio for the first step is determined from (the first voltage)/(the second voltage);

in a second step, the first leakage detection switch and the second leakage detection switch are turned ON, a first voltage for the first leakage detection resistors, and a second voltage, for the second leakage detection resistors are detected, and a second voltage ratio for the second step is determined from (the first voltage)/(the second voltage);

in a third step, the first leakage detection switch is turned ON and the second leakage detection switch is turned OFF, a first voltage for the first leakage detection resistors, and a second voltage, for the second leakage detection resistors are detected, and a third voltage ratio for the third step is determined from (the first voltage)/(the second voltage);

in a fourth step, the first leakage detection switch is turned OFF and the second leakage detection switch is turned ON, a first voltage for the first leakage detection resistors, and a second voltage, for the second leakage detection resistors are detected, and a fourth voltage ratio for the fourth step is determined from (the first voltage)/(the second voltage); and

leakage detection circuit failure is determined from the first voltage ratio, the second voltage ratio, the third voltage ratio, and the fourth voltage ratio.

10. The car power source apparatus as recited in claim 9 wherein the failure detection circuit determines (the third voltage ratio)/(the first voltage ratio), (the fourth voltage ratio)/(the first voltage ratio), (the third voltage ratio)/(the second voltage ratio), and (the fourth voltage ratio)/(the second voltage ratio) from the computed first voltage ratio, the second voltage ratio, the third voltage ratio, and the fourth voltage ratio;

and determines failure of the first series circuit from (the third voltage ratio)/(the first voltage ratio) and (the fourth voltage ratio)/(the second voltage ratio).

11. The car power source apparatus as recited in claim 9 wherein the failure detection circuit determines (the third voltage ratio)/(the first voltage ratio), (the fourth voltage ratio)/(the first voltage ratio), (the third voltage ratio)/(the second voltage ratio), and (the fourth voltage ratio)/(the second voltage ratio) from the computed first voltage ratio, the second voltage ratio, the third voltage ratio, and the fourth voltage ratio;

and determines failure of the second series circuit from (the fourth voltage ratio)/(the first voltage ratio) and (the third voltage ratio)/(the second voltage ratio).

12. The car power source apparatus as recited in claim 10 wherein the failure detection circuit determines failure of the first series circuit by comparing (the third voltage ratio)/(the first voltage ratio) and (the fourth voltage ratio)/(the second voltage ratio) with a set range of values.

13. The car power source apparatus as recited in claim 11 wherein the failure detection circuit determines failure of the second series circuit by comparing (the fourth voltage ratio)/(the first voltage ratio) and (the third voltage ratio)/(the second voltage ratio) with a set range of values.

14. The car power source apparatus as recited in claim 12 wherein the failure detection circuit determines failure of the first leakage detection switch if (the third voltage ratio)/(the first voltage ratio) and (the fourth voltage ratio)/(the second voltage ratio) are both within the set range of values.

15. The car power source apparatus as recited in claim 13 wherein the failure detection circuit determines failure of the second leakage detection switch if (the fourth voltage ratio)/(the first voltage ratio) and (the third voltage ratio)/(the second voltage ratio) are both within the set range of values.

16. The car power source apparatus as recited in claim 9 wherein the failure detection circuit determines failure of the first series circuit and the second series circuit by comparing voltage ratios with the following set range of values.

0.95<

(the third voltage ratio)/(the first voltage ratio)<

1.05 

 

(a)

0.95<

(the fourth voltage ratio)/(the first voltage ratio)<

1.05 

 

(b)

0.95<

(the third voltage ratio)/(the second voltage ratio)<

1.05 

 

(c)

0.95<

(the fourth voltage ratio)/(the second voltage ratio)<

1.05 

 

(d)

17. The car power source apparatus as recited in claim 16 for relations (a) through (d), the failure detection circuit determines failure of the first series circuit when both (a) and (d) are satisfied, and determines failure of the second series circuit when both (b) and (c) are satisfied.