Test system for detecting defective batteries

• US 6,249,125 B1
• Filed: 03/03/2000
• Issued: 06/19/2001
• Est. Priority Date: 03/03/2000
• Status: Expired due to Term

• Current Assignee: National Instruments Corporation (Emerson Electric Company)
• Original Assignee: National Instruments Corporation (Emerson Electric Company)
• Inventors: Marini, Marc, Haddad, Michel
• Primary Examiner(s): Wong, Peter S.
• Assistant Examiner(s): TOATLEY, GREGORY J
• Application Number:
  US09/517,935
• Time in Patent Office: 473 Days
• Field of Search: 320/116, 320/119, 324/426, 702/63
• US Class Current: 324/426
• CPC Class Codes: G01R 31/3865 related to manufacture, e.g. testing after manufacture
• CPC Class Codes: G01R 31/388 involving voltage measurements
• CPC Class Codes: H02J 7/0013 acting upon several batteries simultaneously or sequentially H02J7/1423 takes precedence
• CPC Class Codes: H02J 7/005 Detection of state of health [SOH]

Abstract

A system and method that reduces system cost in testing defective batteries. In a particular embodiment, a test system may be configured to reduce system cost by wiring two-wire relays from a plurality of batteries to a plurality of multiplexers located in a first stage. The number of two-wire relays is equal to:

B/2+4.5 if B is odd

B/2+5 if B is even

where B is the number of batteries. The batteries may be associated with a particular combination of input channels of the multiplexers located in the first stage. The outputs of the multiplexers located in the first stage may then be connected to the inputs of at least one multiplexer located in a second stage. The outputs of the at least one multiplexer located in the second stage may then be connected to at least one instrument, such as a multimeter. Since each battery may be associated with a particular combination of input channels of multiplexers located in the first stage, software may be used to select the particular combination of input channels to be measured by the at least one instrument. The at least one instrument compares the voltage between a particular combination of input channels of multiplexers located in the first stage with an expected value. If the voltage of the particular combination of input channels is less than the expected value, then that particular battery is defective.

Claims

1. A test system for testing a plurality of batteries, wherein each of the batteries include positive and negative nodes connected in series, the system comprising:

a plurality of multiplexers connected to each battery, wherein each of the plurality of multiplexers comprise at least one two-wire relay, wherein the number of two-wire relays is less than the number of the plurality of batteries;

a plurality of wires connecting positive and negative nodes of each of the plurality of batteries to the plurality of multiplexers;

at least one instrument connected to outputs of at least one multiplexer of the plurality of multiplexers, wherein the at least one instrument is configured to receive a voltage from the plurality of batteries, wherein the at least one instrument is operable to test each of the plurality of batteries.

2. The test system as recited in claim 1, wherein the number of two-wire relays is equal to:

B/2+4.5 if B is odd

B/2+5 if B is even

where B is the number of the plurality of batteries.

3. The test system as recited in claim 2, wherein the plurality of multiplexers are located in two stages, wherein at least two multiplexers are located in a first stage, wherein at least one multiplexer is located in a second stage, wherein the at least one instrument is connected to the at least multiplexer located in the second stage.

4. The test system for testing a plurality of batteries as recited in claim 3,

wherein the positive and negative nodes of a first selected batteries are connected to a plurality of input channels of a first multiplexer in the first stage, wherein each input channel is connected to a particular two-wire relay;

wherein the positive and negative nodes of a second selected batteries are connected to a plurality of input channels of a second multiplexer in the first stage, wherein each input channel is connected to a particular two-wire relay.

5. The test system for testing a plurality of batteries as recited in claim 4,

wherein a negative node of a first battery is connected to a positive node of a second neighboring battery;

wherein a particular wire is connected between the negative node of the first battery and the positive node of the second neighboring battery.

6. The test system for testing a plurality of batteries as recited in claim 5,

wherein a positive node of a third battery is connected to a negative node of the second neighboring battery;

wherein a particular wire is connected between the positive node of the third battery and the negative node of the second neighboring battery.

7. The test system for testing a plurality of batteries as recited in claim 6,

wherein each of the plurality of batteries is associated with a selectable combination of the plurality of input channels of the first and second multiplexer located in the first stage.

8. The test system for testing a plurality of batteries as recited in claim 7,

wherein the at least one instrument is operable to monitor a charge/discharge state of each of the plurality of batteries, wherein the at least one instrument is operable to determine a defective battery from each of the plurality of batteries.

9. The test system for testing a plurality of batteries as recited in claim 8,

wherein the at least one instrument measures a voltage between the selectable combination of input channels of the first and second multiplexer located in the first stage,

wherein if the voltage between the selectable combination of input channels is not within a known range, then a battery associated with that selectable combination of input channels is defective.

10. The test system for testing a plurality of batteries as recited in claim 9,

wherein the first and second multiplexer located in the first stage are programmable to selectively provide signals from the plurality of batteries to the at least one multiplexer in the second stage, wherein the at least one instrument connected to the output of the at least one multiplexer in the second stage is operable to individually test each of the plurality of batteries.

11. The test system for testing a plurality of batteries as recited in claim 10, wherein the at least one instrument comprises a plurality of instruments.

12. The test system for testing a plurality of batteries as recited in claim 11, wherein the plurality of wires connect the positive and negative nodes of the first and a fifth battery to the plurality of input channels of the first multiplexer located in the first stage, wherein the plurality of wires connect the positive and negative nodes of the third and a seventh battery to the plurality of input channels of the second multiplexer of the first stage, wherein the plurality of wires connect the positive node of the second and a sixth battery to the plurality of input channels of the first multiplexer located in the first stage, wherein the plurality of wires connect the negative node of the second and sixth battery to the plurality of input channels of the second multiplexer located in the first stage, wherein the plurality of wires connect the positive node of a fourth and eighth battery to the plurality of input channels of the second multiplexer located in the first stage, wherein the plurality of wires connects the negative node of the fourth and eighth battery to the plurality of input channels of the first multiplexer located in the first stage.

13. The test system as recited in claim 12, wherein the test system comprises:

a signal conditioning module, wherein the signal conditioning module comprises the plurality of multiplexers located in two stages, wherein the plurality of multiplexers located in the first stage are connected to each of the plurality of batteries;

a data acquisition card, wherein the data acquisition card is configured to perform as the at least one instrument, wherein the data acquisition card is connected to the signal conditioning module, wherein the data acquisition card is configured to receive the voltage from the plurality of batteries, wherein the data acquisition card is operable to determine a defective battery from the plurality of batteries.

14. A method of testing a plurality of batteries, wherein each of the batteries include positive and negative nodes connected in series, comprising:

connecting the positive and the negative node of the plurality of batteries by a plurality of wires to a plurality of multiplexers, wherein each of the plurality of multiplexers is comprised of at least one two-wire relay, wherein the plurality of two-wire relays is less than the number of the plurality of batteries;

connecting at least one instrument to outputs of at least one multiplexer of the plurality of the multiplexers, wherein the at least one instrument is configured to receive a voltage from the plurality of batteries, wherein the at least one instrument is operable to test each of the plurality of batteries.

15. The method for testing a plurality of batteries as recited in claim 14, wherein the number of two-wire relays is equal to:

B/2+4.5 if B is odd

B/2+5 if B is even

where B is the number of the plurality of batteries.

16. The method as recited in claim 15, wherein the plurality of multiplexers are located in two stages, wherein at least two multiplexers are located in a first stage, wherein at least one multiplexer is located in a second stage, wherein the at least one instrument is connected to the at least one multiplexer located in the second stage.

17. The method for testing a plurality of batteries as recited in claim 16, wherein the positive and negative nodes of a first and fifth battery are connected to input channels of a first multiplexer located in the first stage, wherein the positive and negative nodes of a third and seventh battery are connected to input channels of a second multiplexer located in the first stage, wherein the positive nodes of a second and sixth battery are connected to input channels of the first multiplexer located in the first stage, wherein the negative nodes of the second and sixth battery are connected to input channels of the second multiplexer located in the first stage, wherein the positive nodes of a fourth and eighth battery are connected to input channels of the second multiplexer located in the first stage, wherein the negative nodes of the fourth and eighth battery are connected to input channels of the first multiplexer located in the first stage.

18. The method as recited in claim 17, wherein each of the plurality of batteries is associated with a selectable combination of the plurality of input channels of the first and second multiplexer located in the first stage.

19. The method as recited in claim 18, wherein the at least one instrument measures a voltage between the selectable combination of input channels of the first and second multiplexer located in the first stage, wherein if the voltage between the selectable combination of input channels is not within a known range, then a battery associated with that selectable combination of input channels is defective.

20. The method as recited in claim 19, wherein the at least one instrument comprises a plurality of instruments.