Electricity: measuring and testing – Electrolyte properties – Using a battery testing device
Reexamination Certificate
2000-03-03
2001-06-19
Wong, Peter S. (Department: 2838)
Electricity: measuring and testing
Electrolyte properties
Using a battery testing device
C320S116000, C320S119000, C702S063000
Reexamination Certificate
active
06249125
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to the field of test and measurement systems, and more particularly to a system and method that reduces the system cost of detecting defective batteries.
DESCRIPTION OF THE RELATED ART
Scientists and engineers often use test and measurement and data acquisition systems to perform a variety of functions, including laboratory research, process monitoring and control, data logging, analytical chemistry, test and analysis of physical phenomena and control of mechanical or electrical machinery, to name a few examples. One example of hardware to implement such measuring systems is a computer-based measurement system or data acquisition (DAQ) system. A computer-based measurement or DAQ system typically includes transducers for measuring and providing electrical signals, signal conditioning hardware which may perform amplification, isolation and/or filtering, and measurement or DAQ hardware for receiving digital and analog signals and providing them to a processing system, such as a personal computer. The computer may further include analysis hardware and software for analyzing and appropriately displaying the measured data.
As mentioned above, a measurement system may include one or more of a measurement or DAQ device comprised in or connected to a computer system. The device may be an I/O board plugged into one of the I/O slots of the processing or computer system. The measurement or DAQ device may also comprise an external device connected to a computer system. Exemplary hardware I/O (input/output) interface options include the GPIB (general purpose interface bus), the VXI bus, the PXI bus, or a serial bus such as the RS-232 protocol, IEEE 1394, or USB. As one example, measurement systems can be configured to measure the voltages across batteries and determine if they are defective.
Batteries are comprised of cells connected together to furnish electric current. The current may then be used to provide power to a product. For example, batteries can be found in many types of products such as flashlights, cameras, automobiles, cordless phones, etc.
Prior to the consumer purchasing batteries or the supplier receiving batteries from a manufacturer, the batteries must be tested to ensure the batteries meet certain specifications. One of those specifications is that each battery exhibits a certain voltage. In one test configuration, the voltages of each battery may be tested by connecting a group of batteries in series and then measuring the voltage of each battery with rechargeable batteries connected to a charger. Batteries are connected in series in order to maximize production capacity on the charger system.
Batteries connected in series may be tested in various different configurations. One configuration is to connect each battery to a particular input channel of a single two-wire multiplexer where each input channel is a single pair of wires. The single two-wire multiplexer provides an interface between the batteries and a measurement instrument, such as a multimeter. However, the multiplexer architecture only allows a single pair of wires or a channel to be selected to route the battery voltage information to the instrument. A disadvantage of this configuration is that the number of multiplexer channels or single pair of wires equals the number of batteries.
Another configuration for testing batteries connected in series includes two single-wire multiplexers coupled to a measuring instrument, such as a digital multimeter. The first multiplexer is coupled to the positive terminal of the multimeter; whereas, the second multiplexer is coupled to the negative terminal of the multimeter. The batteries connected in series are connected to the two multiplexers in an arrangement where the positive terminals of the batteries placed in the odd number positions will be connected to the various input channels of the first multiplexer. The positive terminals of the batteries placed in the even number positions will be connected to the various input channels of the second multiplexer. Unfortunately, a disadvantage to this configuration is that the number of multiplexer channels or single-wire relays is equal to the number of batteries.
It would therefore be desirable to develop a system and method for testing a plurality of batteries that would reduce wiring and relays or switches in order to reduce system cost.
SUMMARY OF THE INVENTION
The problems outlined above are in large part solved by a system and method that reduces system cost in detecting defective batteries out of a plurality of batteries connected in series. According to one embodiment of the present invention, a plurality of multiplexers are connected to each battery by a plurality of wires. Each of the plurality of multiplexers comprises at least one two-wire relay. The number of two-wire relays is less than the number of the plurality of batteries when the number of batteries is eleven or greater. In the preferred embodiment, 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. Furthermore, at least one instrument, such as a multimeter, is connected to the outputs of at least one multiplexer of the plurality of multiplexers. The at least one instrument is configured to receive a voltage from each of the plurality of batteries and hence is operable to test each of the plurality of batteries.
In a particular embodiment of the present invention, each battery is connected to various input channels of a plurality of multiplexers located in a first stage. The outputs of multiplexers located in the first stage are connected to various input channels of at least one multiplexer located in a second stage. Each multiplexer of the plurality of multiplexers located in the first and second stage is comprised of at least one two-wire relay. The number of two-wire relays is less than the number of the plurality of batteries when the number of batteries is eleven or greater. Furthermore, each input channel of the multiplexers located in the first and second stage is connected to a two-wire relay. At least one instrument, such as a multimeter, is connected to the outputs of the at least one multiplexer located in the second stage. The at least one instrument is configured to receive a voltage from each of the plurality of batteries. The at least one instrument then compares the received voltage with a known range. If the received voltage is not within the known range, then the battery associated with the received voltage is defective.
In a particular embodiment of the present invention, the batteries may be associated with a particular combination of input channels of the multiplexers located in the first stage. 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 measure. The at least one instrument compares the voltage between a particular combination of input channels of multiplexers located in the first stage with a known range. If the voltage of the particular combination of input channels of the multiplexers located in the first stage is not within the known range, then that particular battery is defective
REFERENCES:
patent: 5710503 (1998-01-01), Sideris et al.
patent: 6094030 (2000-07-01), Gunthrope et al.
Haddad Michel
Marini Marc
Conley Rose & Tayon PC
Hood Jeffrey C.
National Instruments Corporation
Toatley , Jr. Gregory J.
Wong Peter S.
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