U.S. patent application number 09/870410 was filed with the patent office on 2002-03-28 for integrated conductance and load test based electronic battery tester.
Invention is credited to Bertness, Kevin I., Troy, Michael E..
Application Number | 20020036504 09/870410 |
Document ID | / |
Family ID | 27496531 |
Filed Date | 2002-03-28 |
United States Patent
Application |
20020036504 |
Kind Code |
A1 |
Troy, Michael E. ; et
al. |
March 28, 2002 |
Integrated conductance and load test based electronic battery
tester
Abstract
An electronic battery tester for testing a storage battery
includes first and second Kelvin connections configured to couple
to the battery. A forcing function applies a time varying signal to
the battery through the first and second Kelvin connections.
Further, a resistive load is configured to couple across the first
and second terminals of the battery and draw a relatively large
current. The storage battery is tested as a function of a dynamic
parameter measured through the first and second Kelvin connections
and as a function of a response of the storage battery to the
relatively large current drawn through the resistive load.
Inventors: |
Troy, Michael E.; (Lockport,
IL) ; Bertness, Kevin I.; (Batavia, IL) |
Correspondence
Address: |
WESTMAN, CHAMPLIN & KELLY
A PROFESSIONAL ASSOCIATION
SUITE 1600 - INTERNATIONAL CENTRE
900 SECOND AVENUE SOUTH
MINNEAPOLIS
MN
55402-3319
US
|
Family ID: |
27496531 |
Appl. No.: |
09/870410 |
Filed: |
May 30, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09870410 |
May 30, 2001 |
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09293020 |
Apr 16, 1999 |
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09870410 |
May 30, 2001 |
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09703270 |
Oct 31, 2000 |
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60208264 |
May 31, 2000 |
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60163013 |
Nov 1, 1999 |
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Current U.S.
Class: |
324/430 |
Current CPC
Class: |
G01R 31/3648 20130101;
G01R 31/007 20130101; G01R 31/382 20190101; G01R 31/3647 20190101;
G01R 31/389 20190101 |
Class at
Publication: |
324/430 |
International
Class: |
G01N 027/416 |
Claims
What is claimed is:
1. An electronic battery tester for testing a storage battery
comprising: a first Kelvin connection configured to electrically
couple to a first terminal of the battery; a second Kelvin
connection configured to electrically couple to a second terminal
of the battery; a forcing function configured to apply a time
varying signal to the battery through the first and second Kelvin
connections; a load resistance R.sub.L configured to couple across
the first and second terminals of the battery and draw a relatively
large current therethrough; and a microprocessor configured to test
the storage battery as a function of a dynamic parameter measured
through the first and second Kelvin connections in response to
applied time varying signal and as a function of a response of the
storage battery to the relatively large current drawn through the
load resistance.
2. The electronic battery tester of claim 1 wherein the dynamic
parameter is measured by the microprocessor when the load
resistance is coupled across the terminals of the battery.
3. The electronic battery tester of claim 1 wherein the dynamic
parameter is measured by the microprocessor prior to coupling the
load resistance across the terminals of the battery.
4. The electronic battery tester of claim 1 wherein the dynamic
parameter is measured when the load resistance is disconnected from
the first and second terminals of the battery.
5. The electronic battery tester of claim 1 wherein the dynamic
parameter measured when the load resistance is coupled across the
terminals of the battery is compared to the dynamic parameter
measured prior to the load resistance being coupled across the
battery.
6. The electronic battery tester of claim 1 wherein the dynamic
parameter measured when the load resistance is coupled across the
terminals of the battery is compared to the dynamic parameter
measured after the load resistance is disconnected from the
battery.
7. The electronic battery tester of claim 1 wherein the dynamic
parameter measured prior to the load resistance is coupled across
the terminals of the battery is compared to the dynamic parameter
measured after the load resistance is disconnected from the
battery.
8. The electronic battery tester of claim 1 wherein the battery
test is a function of voltage measured while the load resistance is
applied to the battery.
9. The electronic battery tester of claim 1 wherein the battery
test is a function of a slope of the voltage measured while the
load resistance is applied to the battery.
10. The electronic battery tester of claim 9 wherein the battery
test is a function of a change in voltage slope measured while the
load resistance is applied to the battery.
11. The electronic battery tester of claim 1 wherein the battery
test is a function of the difference in a voltage measured while
the load resistance is applied to the battery and a voltage prior
to application of the load.
12. The electronic battery tester of claim 1 wherein the battery
test is a function of a voltage measured subsequent to
disconnection of the load resistance from the battery.
13. The electronic battery tester of claim 1 wherein the battery
test is a function of a slope of the voltage measured subsequent to
disconnection of the load resistance from the battery.
14. The electronic battery tester of claim 1 wherein the battery
test is a function of a change in voltage slope measured subsequent
to disconnection of the load resistance from the battery.
15. The electronic battery tester of claim 1 wherein the battery
test is a function of a difference in voltage measured while the
load resistance is applied to the battery and a voltage after
disconnection of the load.
16. The electronic battery tester of claim 1 wherein a duration of
application of the load resistance is variable.
17. The electronic battery tester of claim 1 wherein the duration
of voltage measurements subsequent to removal of the load
resistance is variable.
18. The electronic battery tester of claim 1 wherein the resistance
of the load resistance is variable.
19. The electronic battery tester of claim 18 wherein the variable
load is controlled by the microprocessor.
20. The electronic battery tester of claim 1 wherein a pass/fail
voltage threshold measured while the load resistance is applied is
determined by the microprocessor as a function of the measured
dynamic parameter.
21. The electronic battery tester of claim 1 wherein the
microprocessor provides a state of health output as a function of
the test.
22. The electronic battery tester of claim 1 wherein the
microprocessor provides an output indicative of a sulfated battery
as a function of the test.
23. The electronic battery tester of claim 1 wherein the
microprocessor provides a battery life expectancy output as a
function of the test.
24. The electronic battery tester of claim 1 wherein the
microprocessor provides an output indicative of a shorted cell
within the storage battery.
25. The electronic battery tester of claim 24 wherein an indication
of the shorted cell is a function of a voltage measured while the
load resistance is coupled across the battery.
26. The electronic battery tester of claim 24 wherein an indication
of the shorted cell is a function of a voltage slope measured while
the load resistance is coupled across the battery.
27. The electronic battery tester of claim 24 wherein an indication
of the shorted cell is a function of a voltage slope measured after
the load resistance is disconnected from the battery.
28. The electronic battery tester of claim 24 wherein an indication
of the shorted cell is a function of a voltage difference after the
load resistance is disconnected from the battery compared with a
voltage prior to application of the load resistance.
29. The electronic battery tester of claim 1 wherein the load
resistance is coupled to the battery through the first and second
Kelvin connections.
30. The electronic battery tester of claim 1 wherein the
microprocessor provides an output indicative of an open circuit in
the battery.
31. The electronic battery tester of claim 30 wherein the
indication of an open circuit is a function of an open circuit
voltage measurement across the battery and a load voltage
measurement across the battery obtained while the load resistance
is applied to the battery.
32. The electronic battery tester of claim 30 wherein the
indication of an open circuit is a function of the slope of a
voltage measurement across the battery after the load is
disconnected from the battery.
33. The electronic battery tester of claim 1 wherein the
microprocessor applies the load resistance to the battery prior to
measuring the dynamic parameter to thereby reduce a surface charge
voltage associated with the battery.
34. The electronic battery tester of claim 33 wherein the test is a
function of battery voltage subsequent to the reduction of surface
charge.
35. The electronic battery tester of claim 1 wherein the resistance
load is connected externally to the tester.
36. The electronic battery tester of claim 35 wherein the resistive
load is located within a Kelvin cable assembly.
Description
[0001] The present application is based on and claims the benefit
of U.S. Provisional Patent Application Serial No. 60/208,264, filed
May 31, 2000, the content of which is hereby incorporated by
reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to storage batteries. More
specifically, the present invention relates to electronic battery
testers used to test storage batteries.
[0003] Storage batteries, such as lead acid storage batteries, are
used in a variety of applications such as automotive vehicles and
standby power sources. Typical storage batteries consist of a
plurality of individual storage cells which are electrically
connected in series. Each cell can have a voltage potential of
about 2.1 volts, for example. By connecting the cells in the
series, the voltages of the individual cells are added in a
cumulative manner. For example, in a typical automotive storage
battery, six storage cells are used to provide a total voltage of
about 12.6 volts. The individual cells are held in a housing and
the entire assembly is commonly referred to as the "battery."
[0004] It is frequently desirable to ascertain the condition of a
storage battery. Various testing techniques have been developed
over the long history of storage batteries. For example, one
technique involves the use of a hygrometer in which the specific
gravity of the acid mixture in the battery is measured. Electrical
testing has also been used to provide less invasive battery testing
techniques. A very simple electrical test is to simply measure the
voltage across the battery. If the voltage is below a certain
threshold, the battery is determined to be bad. Another technique
for testing a battery is referred to as a load test. In a load
test, the battery is discharged using a known load. As the battery
is discharged, the voltage across the battery is monitored and used
to determine the condition of the battery. More recently,
techniques have been pioneered by Dr. Keith S. Champlin and
Midtronics, Inc. of Willowbrook, Ill. for testing storage battery
by measuring a dynamic parameter of the battery such as the dynamic
conductance of the battery. These techniques are described in a
number of United States patents, for example, U.S. Pat. No.
3,873,911, issued Mar. 25, 1975, to Champlin, entitled ELECTRONIC
BATTERY TESTING DEVICE; U.S. Pat. No. 3,909,708, issued Sep. 30,
1975, to Champlin, entitled ELECTRONIC BATTERY TESTING DEVICE; U.S.
Pat. No. 4,816,768, issued Mar. 28, 1989, to Champlin, entitled
ELECTRONIC BATTERY TESTING DEVICE; U.S. Pat. No. 4,825,170, issued
Apr. 25, 1989, to Champlin, entitled ELECTRONIC BATTERY TESTING
DEVICE WITH AUTOMATIC VOLTAGE SCALING; U.S. Pat. No. 4,881,038,
issued Nov. 14, 1989, to Champlin, entitled ELECTRONIC BATTERY
TESTING DEVICE WITH AUTOMATIC VOLTAGE SCALING TO DETERMINE DYNAMIC
CONDUCTANCE; U.S. Pat. No. 4,912,416, issued Mar. 27, 1990, to
Champlin, entitled ELECTRONIC BATTERY TESTING DEVICE WITH
STATE-OF-CHARGE COMPENSATION; U.S. Pat. No. 5,140,269, issued Aug.
18, 1992, to Champlin, entitled ELECTRONIC TESTER FOR ASSESSING
BATTERY/CELL CAPACITY; U.S. Pat. No. 5,343,380, issued Aug. 30,
1994, entitled METHOD AND APPARATUS FOR SUPPRESSING TIME VARYING
SIGNALS IN BATTERIES UNDERGOING CHARGING OR DISCHARGING; U.S. Pat.
No. 5,572,136, issued Nov. 5, 1996, entitled ELECTRONIC BATTERY
TESTER WITH AUTOMATIC COMPENSATION FOR LOW STATE-OF-CHARGE; U.S.
Pat. No. 5,574,355, issued Nov. 12, 1996, entitled METHOD AND
APPARATUS FOR DETECTION AND CONTROL OF THERMAL RUNAWAY IN A BATTERY
UNDER CHARGE; U.S. Pat. No. 5,585,728, issued Dec. 17, 1996,
entitled ELECTRONIC BATTERY TESTER WITH AUTOMATIC COMPENSATION FOR
LOW STATE-OF-CHARGE; U.S. Pat. No. 5,592,093, issued Jan. 7, 1997,
entitled ELECTRONIC BATTERY TESTING DEVICE LOOSE TERMINAL
CONNECTION DETECTION VIA A COMPARISON CIRCUIT; U.S. Pat. No.
5,598,098, issued Jan. 28, 1997, entitled ELECTRONIC BATTERY TESTER
WITH VERY HIGH NOISE IMMUNITY; U.S. Pat. No. 5,757,192, issued May
26, 1998, entitled METHOD AND APPARATUS FOR DETECTING A BAD CELL IN
A STORAGE BATTERY; U.S. Pat. No. 5,821,756, issued Oct. 13, 1998,
entitled ELECTRONIC BATTERY TESTER WITH TAILORED COMPENSATION FOR
LOW STATE-OF-CHARGE; U.S. Pat. No. 5,831,435, issued Nov. 3, 1998,
entitled BATTERY TESTER FOR JIS STANDARD; U.S. Pat. No. 5,914,605,
issued Jun. 22, 1999, entitled ELECTRONIC BATTERY TESTER; U.S. Pat.
No. 5,945,829, issued Aug. 31, 1999, entitled MIDPOINT BATTERY
MONITORING; U.S. Pat. No. 6,002,238, issued Dec. 14, 1999, entitled
METHOD AND APPARATUS FOR MEASURING COMPLEX IMPEDANCE OF CELLS AND
BATTERIES; U.S. Pat. No. 6,037,777, issued Mar. 14, 2000, entitled
METHOD AND APPARATUS FOR DETERMINING BATTERY PROPERTIES FROM
COMPLEX IMPEDANCE/ADMITTANCE; U.S. Pat. No. 6,051,976, issued Apr.
18, 2000, entitled METHOD AND APPARATUS FOR AUDITING A BATTERY
TEST; U.S. Pat. No. 6,081,098, issued Jun. 27, 2000, entitled
METHOD AND APPARATUS FOR CHARGING A BATTERY; U.S. Pat. No.
6,091,245, issued Jul. 18, 2000, entitled METHOD AND APPARATUS FOR
AUDITING A BATTERY TEST; U.S. Pat. No. 6,104,167, issued Aug. 15,
2000, entitled METHOD AND APPARATUS FOR CHARGING A BATTERY; U.S.
Pat. No. 6,137,269, issued Oct. 24, 2000, entitled METHOD AND
APPARATUS FOR ELECTRONICALLY EVALUATING THE INTERNAL TEMPERATURE OF
AN ELECTROCHEMICAL CELL OR BATTERY; U.S. Pat. No. 6,163,156, issued
Dec. 19, 2000, entitled ELECTRICAL CONNECTION FOR ELECTRONIC
BATTERY TESTER; U.S. Pat. No. 6,172,483, issued Jan. 9, 2001,
entitled METHOD AND APPARATUS FOR MEASURING COMPLEX IMPEDANCE OF
CELL AND BATTERIES; U.S. Pat. No. 6,172,505, issued Jan. 9, 2001,
entitled ELECTRONIC BATTERY TESTER; U.S. Pat. No. 6,222,369, issued
Apr. 24, 2001, entitled METHOD AND APPARATUS FOR DETERMINING
BATTERY PROPERTIES FROM COMPLEX IMPEDANCE/ADMITTANCE; U.S. Pat. No.
6,225,808, issued May 1, 2001, entitled TEST COUNTER FOR ELECTRONIC
BATTERY TESTER; U.S. Ser. No. 09/293,020, filed Apr. 16, 1999,
entitled AUTOMOTIVE BATTERY CHARGING SYSTEM TESTER; U.S. Ser. No.
09/544,696, filed Apr. 7, 2000, entitled ELECTRONIC BATTERY TESTER;
U.S. Ser. No. 09/304,315,filed May 3, 1999, entitled MIDPOINT
BATTERY MONITOR"; U.S. Ser. No. 09/290,133, filed Mar. 26, 1999,
entitled ELECTRONIC BATTERY TESTER; U.S. Ser. No. 09/560,920, filed
Apr. 28, 2000, entitled MULTI-LEVEL CONDUCTANCE TESTER; U.S. Ser.
No. 09/431,446, filed Nov. 1, 1999, entitled ALTERNATOR DIAGNOSTIC
SYSTEM; U.S. Ser. No. 09/432,473, filed Nov. 1, 1999, entitled
ELECTRONIC BATTERY TESTER WITH INTERNAL BATTERY; U.S. Ser. No.
09/388,501, filed Sep. 1, 1999, entitled METHOD AND APPARATUS FOR
EVALUATING STORED CHARGE IN AN ELECTROCHEMICAL CELL OR BATTERY;
U.S. Ser. No. 069/703,270, filed Oct. 31, 2000, entitled ELECTRONIC
BATTERY TESTER; U.S. Ser. No. 09/503,015, filed Feb. 11, 2000,
entitled METHOD AND APPARATUS FOR MEASURING COMPLEX ADMITTANCE OF
CELLS AND BATTERIES; U.S. Ser. No. 09/564,740, filed May 4, 2000,
entitled ENERGY MANAGEMENT SYSTEM FOR AUTOMOTIVE VEHICLE; U.S. Ser.
No. 09/575,629, filed May 22, 2000, entitled VEHICLE ELECTRICAL
SYSTEM TESTER WITH ENCODED OUTPUT; U.S. Ser. No. 09/780,146,filed
Feb. 9, 2001, entitled STORAGE BATTERY WITH INTEGRAL BATTERY
TESTER; U.S. Ser. No. 09/575,627, filed May 22, 2000, entitled
METHOD AND APPARATUS FOR CHARGING A BATTERY; U.S. Ser. No.
09/577,421, filed May 22, 2000, entitled METHOD AND APPARATUS FOR
CHARGING A BATTERY; U.S. Ser. No. 09/816,768, filed March 23, 2001,
entitled MODULAR BATTERY TESTER; U.S. Ser. No. 09/662,401, filed
Sep. 14, 2000, entitled TESTING PARALLEL STRINGS OF STORAGE
BATTERIES; U.S. Ser. No. 09/662,092, filed Sep. 14, 2000, entitled
ELECTRONIC BATTERY TESTER FOR TESTING PARALLEL STRINGS OF STORAGE
BATTERIES; U.S. Ser. No. 09/654,715, filed Sep. 5, 2000, entitled
APPARATUS FOR CALIBRATING ELECTRONIC BATTERY TESTER; U.S. Ser. No.
09/691,586, filed Oct. 18, 2000, entitled METHOD AND APPARATUS FOR
ELECTRONICALLY EVALUATING THE INTERNAL TEMPERATURE OF AN
ELECTROCHEMICAL CELL OR BATTERY; U.S. Ser. No. 09/710,031, filed
Nov. 10, 2000, entitled METHOD AND APPARATUS FOR MEASURING COMPLEX
SELF-IMMITTANCE OF A GENERAL ELECTRICAL ELEMENT; U.S. Ser. No.
09/740,254, filed Dec. 18, 2000, entitled ELECTRICAL CONNECTION FOR
ELECTRONIC BATTERY TESTER; U.S. Ser. No. 09/756,638, filed Jan. 8,
2001, entitled METHOD AND APPARATUS FOR DETERMINING BATTERY
PROPERTIES FROM COMPLEX IMPEDANCE/ADMITTANCE; U.S. Ser. No.
09/______, filed May 21, 2001, entitled METHOD AND APPARATUS FOR
TESTING CELLS AND BATTERIES EMBEDDED IN SERIES/PARALLEL SYSTEMS;
U.S. Ser. No. 09/483,623, filed Jan. 13, 2000, entitled ALTERNATOR
TESTER; and U.S. Ser. No. 09/361,487, filed Jul. 26, 1999, entitled
APPARATUS AND METHOD FOR CARRYING OUT DIAGNOSTIC TESTS ON BATTERIES
FOR RAPIDLY CHARGING BATTERIES.
SUMMARY OF THE INVENTION
[0005] An electronic battery tester for testing a storage battery
includes first and second Kelvin connections configured to couple
to the battery. A forcing function applies a time varying signal to
the battery through the first and second Kelvin connections.
Further, a resistive load is configured to couple across the first
and second terminals of the battery and draw a relatively large
current. The storage battery is tested as a function of a dynamic
parameter measured through the first and second Kelvin connections
and as a function of a response of the storage battery to the
relatively large current drawn through the resistive load.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is a simplified block diagram showing an electronic
battery tester in accordance with one embodiment of the present
invention.
[0007] FIG. 2 is a simplified block diagram showing steps in
accordance with one aspect of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0008] The present invention includes an electronic battery tester
which measures a dynamic parameter of a battery. The dynamic
parameter is measured in response to a small forcing function
applied across the battery. The forcing function includes a time
varying component and can be any type of periodic or transient
signal with such a component. Typically, the forcing function will
have a relatively small amplitude and can be any type of voltage or
current signal either drawn from or applied to the battery. The
battery tester includes a resistive load capable of drawing a large
current from the battery. A battery test is performed on the
battery which provides a test result as a function both of the
dynamic parameter and a response of the battery of the applied load
resistance. The particular response observed or application of the
load can vary for various embodiments. In one aspect the dynamic
parameter is measured using Kelvin connections across the battery.
In some embodiments the resistive load is connected across the
battery using the same Kelvin connections. The combination of a
test which uses a dynamic parameter as well as a load resistance
can provide improved accuracy in determining the condition of the
storage battery. The internal resistive load can also apply to
alternator and starter testing for testing the charging system and
starter motor of an automotive vehicle.
[0009] FIG. 1 is a simplified block diagram of electronic battery
tester 10 in accordance with one aspect of the invention. Tester 10
includes electronic battery test circuit 16 which couples to
battery 12 through Kelvin connections 18. Circuitry 16 determines
the battery conductance of a battery 12. Circuitry 16 includes
forcing function 50, differential amplifier 52, analog-to-digital
converter 54 and microprocessor 56. Amplifier 52 is capacitively
coupled to battery 12 through capacitance C1 and C2, and has an
output connected to an input of analog-to-digital converter 54.
Microprocessor 56 is connected to system clock 58, memory 60, and
warning indicator 62, an input 66 and provides a data output, such
as for a display.
[0010] In operation, forcing function 50 is controlled by
microprocessor 56 and provides a current in the direction shown by
the arrow in the figure. In one embodiment, this is square wave or
a pulse. Typically, source 50 is a small load applied to battery
12. Differential amplifier 52 is connected to terminals 22 and 24
of battery 12 and provides an output related to the voltage
difference between these terminals. Amplifier 52 has a high input
impedance. Note that circuitry 16 is connected to battery 12
through a four-point connection technique known as a Kelvin
connection. Because very little current flows through amplifier 52
which has a large input impedance, the voltage drop through its
connections to battery 12 is insignificant. The output of
differential amplifier 52 is converted to digital format and
provided to microprocessor 56. Microprocessor 56 operates at a
frequency determined by system clock 58 according to program
instructions stored in memory 60.
[0011] Microprocessor 56 determines the dynamic conductance of
battery 12 by applying a current pulse with forcing function 50.
Forcing function 50 comprises a small load or an active source. The
microprocessor determines the change in battery voltage due to the
current pulse using amplifier 52 and analog-to-digital converter
54. The amount of current I generated by forcing function 50 is
known or can be measured and stored in memory 60. Microprocessor 56
calculates the conductance of battery 12 as follows: 1 Conductance
= G = I V Eq . 1
[0012] where .DELTA.I is the change in current flowing through
battery 12 due to forcing function 50, and .DELTA.V is the change
in battery voltage due to applied current .DELTA.I. The relative
conductance of battery 12, can be calculated using the equation: 2
Relative Conductance ( % ) = G measured G reference .times. 100 Eq
. 2
[0013] where G.sub.measured is the measured battery conductance in
accordance with Equation 1 and G.sub.reference is a reference
conductance value stored in memory 60 which can be received through
input 66. Generally, this reference conductance is determined based
upon the type and characteristics of battery 12. Microprocessor 56
can also operate using impedance, admittance, or resistance
measurements.
[0014] FIG. 1 also shows a load resistor 70 labeled R.sub.L coupled
across terminals 22 and 24 of battery 12 and in series with switch
72. Switch 72 is coupled to and controlled by microprocessor 56 to
selectively switch resistive load R.sub.L in series with battery
12. Microprocessor 56 operates to perform the various tests as
discussed above to determine the condition of the battery 12.
[0015] FIG. 2 is a simplified block diagram 100 which illustrates
steps performed by microprocessor 56 based upon instructions stored
in memory 60 in one example embodiment. The test procedure starts
at block 102 and control is passed to block 104. A dynamic
parameter of battery 12 is measured, using any appropriate
technique, such as the technique discussed above. At block 106,
load resistance 70 R.sub.L is applied by microprocessor 56 through
the actuation of switch 72. Microprocessor 56 observes a response
of battery 12. For example, in the embodiment shown in FIG. 1,
microprocessor 56 can observe the voltage or voltage change across
battery 12 in response to the applied resistance R.sub.L using
analog to digital converter 54. At block 108, microprocessor 56
provides a test result output, for example on the data output, of
the dynamic parameter measured at step 104 and the load resistance
and response observed at step 106. The particular order of the
steps or tests performed can be changed accordingly. The procedure
terminates at block 110.
[0016] The particular test performed using the addition of the load
resistance can be any battery test which provides a result which is
a function of a dynamic parameter measurement and the applied load.
In one example, the battery test result is a function of the
measured dynamic parameter with the resistive load R.sub.L on. This
can be combined with a dynamic parameter measurement with the
resistive load off. Other example load measurements which can be
combined with the dynamic parameter measurement include monitoring
the battery voltage over an adjustable time period while the load
is applied. This can be combined with monitoring the voltage during
a recovering period after the load is removed. In one embodiment
load R.sub.L is a variable load which can be controlled, for
example, by microprocessor 56 during the testing process. The
response of the battery to the application of the variable load and
changing of the variable load can be monitored as well as its
response once the load is removed. In a specific example, the
relative conductance determined in accordance with Equation 2 can
be used as a multiplier against the nominal voltage of the battery,
for example 12.7 volts, and again multiplied by a constant. This
value can then be compared to the voltage of the battery measured
at a particular time during application of the load resistance or
after its removal. The various measurements can also be correlated
with the state of health and/or the battery life expectancy which
can then be provided as an output.
[0017] The voltage when the load is applied can also be compared to
a voltage range which can indicate that the battery 12 has a bad
cell. This can then be provided as an output or a warning can be
indicated using output 62. In a more specific example, a bad cell
can be detected if a voltage measured with the load applied at a
first time and a voltage measured at a second time are within a
range, such as 8.0 volts to 8.8 volts (two bad cells) or 10.1 volts
to 10.9 volts (one bad cell), microprocessor 56 can determine that
a bad cell exists in battery 12 and provide an appropriate output.
Additionally, microprocessor 56 can determine if a battery has an
open circuit by using the measured dynamic parameter in conjunction
with the change in voltage across battery 12 with and without the
resistive load R.sub.L applied. The resistance R.sub.L can also be
used to remove a surface charge (a positive voltage polarization)
on battery 12. Once the surface charge is removed, microprocessor
56 can compensate the dynamic parameter measurement in determining
battery condition based upon the measured voltage after removal of
surface charge.
[0018] The correlation between the dynamic parameter and
measurements taken which are a function of the load resistance
R.sub.L to the condition of battery 12 can be determined by
repeated laboratory tests to develop trends or equations which
describe the relationship. Any appropriate technique can be used
including models which model the battery, the use of multiple
measurements to develop a model, neural networks, etc. Although the
load resistance R.sub.L is shown in FIG. 1 as being coupled to the
battery 12 through the Kelvin connections 18, any appropriate
electrical coupling technique can be used. This includes the use of
fifth or sixth additional electrical contacts to terminals 22 and
24. Additionally, in one embodiment all four of the electrical
contacts shown in Kelvin connections 18 are used to couple the
resistive load R.sub.L to battery 12. The duration of the
application of the resistive load R.sub.L or frequency of the
application, can be chosen as appropriate for a desired testing
format.
[0019] In one aspect, circuitry 10 provides an alternator tester
for testing an alternator of a vehicle. In such an embodiment, the
load resistance R.sub.L is used to apply an additional load to the
electrical system of the vehicle. The response of the alternator
and regulator of the automotive vehicle can be observed and the
microprocessor 56 can provide an output indicative of the condition
of the alternator and/or regulator. If the load resistance R.sub.L
is a variable resistor, the voltage across the battery 12, or some
other point in the electrical system, can be observed as various
resistive loads are placed on the system.
[0020] The dynamic parameter used in the present invention can be
obtained in accordance with any appropriate technique. Various
examples and aspects of battery testing are shown in the following
references which are incorporated herein by reference in their
entirety: U.S. Pat. No. 3,873,911, issued Mar. 25, 1975, to
Champlin, entitled ELECTRONIC BATTERY TESTING DEVICE; U.S. Pat. No.
3,909,708, issued Sep. 30, 1975, to Champlin, entitled ELECTRONIC
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ELECTRONIC BATTERY TESTING DEVICE WITH AUTOMATIC VOLTAGE SCALING;
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TESTING DEVICE WITH STATE-OF-CHARGE COMPENSATION; U.S. Pat. No.
5,140,269, issued Aug. 18, 1992, to Champlin, entitled ELECTRONIC
TESTER FOR ASSESSING BATTERY/CELL CAPACITY; U.S. Pat. No.
5,343,380, issued Aug. 30, 1994, entitled METHOD AND APPARATUS FOR
SUPPRESSING TIME VARYING SIGNALS IN BATTERIES UNDERGOING CHARGING
OR DISCHARGING; U.S. Pat. No. 5,572,136, issued Nov. 5, 1996,
entitled ELECTRONIC BATTERY TESTER WITH AUTOMATIC COMPENSATION FOR
LOW STATE-OF-CHARGE; U.S. Pat. No. 5,574,355, issued Nov. 12, 1996,
entitled METHOD AND APPARATUS FOR DETECTION AND CONTROL OF THERMAL
RUNAWAY IN A BATTERY UNDER CHARGE; U.S. Pat. No. 5,585,728, issued
Dec. 17, 1996, entitled ELECTRONIC BATTERY TESTER WITH AUTOMATIC
COMPENSATION FOR LOW STATE-OF-CHARGE; U.S. Pat. No. 5,592,093,
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LOOSE TERMINAL CONNECTION DETECTION VIA A COMPARISON CIRCUIT; U.S.
Pat. No. 5,598,098, issued Jan. 28, 1997, entitled ELECTRONIC
BATTERY TESTER WITH VERY HIGH NOISE IMMUNITY; U.S. Pat. No.
5,757,192, issued May 26, 1998, entitled METHOD AND APPARATUS FOR
DETECTING A BAD CELL IN A STORAGE BATTERY; U.S. Pat. No. 5,821,756,
issued Oct. 13, 1998, entitled ELECTRONIC BATTERY TESTER WITH
TAILORED COMPENSATION FOR LOW STATE-OF-CHARGE; U.S. Pat. No.
5,831,435, issued Nov. 3, 1998, entitled BATTERY TESTER FOR JIS
STANDARD; U.S. Pat. No. 5,914,605, issued Jun. 22, 1999, entitled
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6,002,238, issued Dec. 14, 1999, entitled METHOD AND APPARATUS FOR
MEASURING COMPLEX IMPEDANCE OF CELLS AND BATTERIES; U.S. Pat. No.
6,037,777, issued Mar. 14, 2000, entitled METHOD AND APPARATUS FOR
DETERMINING BATTERY PROPERTIES FROM COMPLEX IMPEDANCE/ADMITTANCE;
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APPARATUS FOR AUDITING A BATTERY TEST; U.S. Pat. No. 6,081,098,
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6,104,167, issued Aug. 15, 2000, entitled METHOD AND APPARATUS FOR
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entitled METHOD AND APPARATUS FOR ELECTRONICALLY EVALUATING THE
INTERNAL TEMPERATURE OF AN ELECTROCHEMICAL CELL OR BATTERY; U.S.
Pat. No. 6,163,156, issued Dec. 19, 2000, entitled ELECTRICAL
CONNECTION FOR ELECTRONIC BATTERY TESTER; U.S. Pat. No. 6,172,483,
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COMPLEX IMPEDANCE OF CELL AND BATTERIES; U.S. Pat. No. 6,172,505,
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No. 6,222,369, issued Apr. 24, 2001, entitled METHOD AND APPARATUS
FOR DETERMINING BATTERY PROPERTIES FROM COMPLEX
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2000, entitled ELECTRONIC BATTERY TESTER; U.S. Ser. No. 09/304,315,
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TESTER; U.S. Ser. No. 09/560,920, filed Apr. 28, 2000, entitled
MULTI-LEVEL CONDUCTANCE TESTER; U.S. Ser. No. 09/431,446, filed
Nov. 1, 1999, entitled ALTERNATOR DIAGNOSTIC SYSTEM; U.S. Ser. No.
09/432,473, filed Nov. 1, 1999, entitled ELECTRONIC BATTERY TESTER
WITH INTERNAL BATTERY; U.S. Ser. No. 09/388,501, filed Sep. 1,
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AN ELECTROCHEMICAL CELL OR BATTERY; U.S. Ser. No. 069/703,270,
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FOR MEASURING COMPLEX ADMITTANCE OF CELLS AND BATTERIES; U.S. Ser.
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SYSTEM FOR AUTOMOTIVE VEHICLE; U.S. Ser. No. 09/575,629, filed May
22, 2000, entitled VEHICLE ELECTRICAL SYSTEM TESTER WITH ENCODED
OUTPUT; U.S. Ser. No. 09/780,146, filed Feb. 9, 2001, entitled
STORAGE BATTERY WITH INTEGRAL BATTERY TESTER; U.S. Ser. No.
09/575,627, filed May 22, 2000, entitled METHOD AND APPARATUS FOR
CHARGING A BATTERY; U.S. Ser. No. 09/577,421, filed May 22, 2000,
entitled METHOD AND APPARATUS FOR CHARGING A BATTERY; U.S. Ser. No.
09/816,768, filed Mar. 23, 2001, entitled MODULAR BATTERY TESTER;
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PARALLEL STRINGS OF STORAGE BATTERIES; U.S. Ser. No. 09/662,092,
filed Sep. 14, 2000, entitled ELECTRONIC BATTERY TESTER FOR TESTING
PARALLEL STRINGS OF STORAGE BATTERIES; U.S. Ser. No. 09/654,715,
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entitled METHOD AND APPARATUS FOR ELECTRONICALLY EVALUATING THE
INTERNAL TEMPERATURE OF AN ELECTROCHEMICAL CELL OR BATTERY; U.S.
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APPARATUS FOR MEASURING COMPLEX SELF-IMMITTANCE OF A GENERAL
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APPARATUS FOR DETERMINING BATTERY PROPERTIES FROM COMPLEX
IMPEDANCE/ADMITTANCE; U.S. Ser. No. 09/______, filed May 21, 2001,
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EMBEDDED IN SERIES/PARALLEL SYSTEMS; U.S. Ser. No. 09/483,623,
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CARRYING OUT DIAGNOSTIC TESTS ON BATTERIES FOR RAPIDLY CHARGING
BATTERIES.
[0021] In various aspects, the dynamic parameter is measured prior
to, during or subsequent to application of the load resistance
across terminals of the battery. Further, the measured dynamic
parameter can be compared with dynamic parameters measured at other
periods in time, for example, dynamic parameters obtained prior to,
during or subsequent to application of the load resistance can be
compared with each other. Voltage measurements can be obtained and
a slope of the voltage measurement can be calculated and used in
the battery test. In one example, the battery test is a function of
a slope of the voltage measured while the load resistance is
applied to the battery. The change in voltage slope can be used in
the battery test The voltage slope can be measured subsequent to
disconnection of the load resistance from the battery. The battery
test can be based upon a change in the voltage measured subsequent
to disconnection of the load resistance from the battery. The
battery test can be a function of a difference in voltage measured
while the load resistance is applied to the battery and a voltage
measured after disconnection of the load. In one aspect, the output
from the battery test can provide an indication that the battery
has become sulfated. The voltage slope measured before, during or
after removal of the load resistance can be used in the battery
test. The voltage slope, particularly the voltage slope after
disconnection of the load from the battery, can be used as an
indication of an open circuit. In one embodiment, the load
resistance 70 shown in FIG. 1 is located external to the battery
tester. For example, the load resistance is placed directly in the
cable assembly used for Kelvin connections 18.
[0022] Although the present invention has been described with
reference to preferred embodiments, workers skilled in the art will
recognize that changes may be made in form and detail without
departing from the spirit and scope of the invention.
* * * * *