Patent Publication Number: US-2002010558-A1

Title: Storage battery with integral battery tester

Description:
[0001] The present application is based on and claims the benefit of U.S. provisional patent application Serial No. 60/181,854, filed Feb. 11, 2000; U.S. Provisional patent application Serial No. 60/204,345, filed May 15, 2000; U.S. provisional patent application Serial No. 60/218,878, filed Jul. 18, 2000; and U.S. provisional patent application Serial No. 60/224,092, filed Aug. 9, 2000, the contents of which are hereby incorporated by reference in their entirety, and is a Continuation-In-Part of and claims priority of U.S. patent application Ser. No. 09/544,696, filed Apr. 7, 2000, which claims the benefit of priority of U.S. provisional patent application Serial No. 60/128,366, filed Apr. 8, 1999, the contents of which are hereby incorporated by reference in their entirety. 
    
    
     
       BACKGROUND OF THE INVENTION  
       [0002] The present invention relates to storage batteries. More specifically, the present invention relates to storage batteries with integral battery testers.  
       [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, a technique has 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. This technique is 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; and U.S. Pat. No. 6,172,505, issued Jan. 9, 2001, entitled ELECTRONIC BATTERY TESTER.  
       [0005] In general, battery testers have been separate pieces of equipment which can be moved between storage batteries and electrically coupled to a storage battery. The prior art has lacked a simple technique for the testing of a storage battery without relying on separate testing equipment.  
       SUMMARY OF THE INVENTION  
       [0006] A storage battery includes a battery housing and a plurality of electrochemical cells in the battery housing electrically connected in series to a positive terminal of the battery and a negative terminal of the battery. A first connection is coupled to the positive terminal of the battery and a second connection is coupled to the negative terminal of the battery. A battery test module is mounted to the battery housing and electrically coupled to the positive and negative terminals through the respective first and second Kelvin connection. A display or other output is configured to output a battery test result from the battery test module. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0007]FIG. 1 is a side plan view of a storage battery including a battery test module in accordance with the present invention.  
     [0008]FIGS. 2A and 2B are top plan views of the storage battery of FIG. 1.  
     [0009]FIG. 3 is a side cross-sectional view of the storage battery of FIGS. 1 and 2 taken along the line labeled  3 — 3  in FIG. 2.  
     [0010]FIG. 4 is a block diagram of a storage battery in accordance with the present invention.  
     [0011]FIG. 5 is an electrical diagram of one example embodiment.  
     [0012]FIG. 6 is an electrical diagram of another example embodiment. 
    
    
     DETAILED DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS  
     [0013] In one aspect of the present invention a storage battery is provided having an integrated battery test module for performing a battery test on electrical cells of the storage battery. As used herein “integrated” can include a separate module which is attached to the battery housing. In one embodiment, the battery test module is electrically coupled to the electrical cells of the storage battery through Kelvin connections. In certain aspects, Kelvin connections are not used. As the battery test module is integral with the battery, an operator can test the battery without relying on external battery test equipment. In one embodiment, the battery test is one that can be easily performed by an unskilled operator. Further, the battery test module is preferably manufactured using low cost techniques which may be integrated with a storage battery without an excessive increase in the cost to produce the battery.  
     [0014]FIG. 1 is a side plan view of a storage battery  10  in accordance with the present invention. Storage battery  10  includes a positive terminal  12  and a negative terminal  14 . A battery test module  16  is mounted to a housing  18  of the storage battery.  
     [0015]FIGS. 2A and 2B are top plan views of the storage battery  10  of FIG. 1. As illustrated in FIG. 2A, battery test module  16  includes an optional input  20  and optional outputs  22  and  24 . Input  20  can be, for example, a push button or other input which can be actuated by an operator. Output  22  can be, for example, an LED or other type of visual indicator which provides a pass/fail indication of a battery test. However, in other aspects, output  24  can be used to send data, using any appropriate technique, to a remote computer or monitoring system. Output  24  can be used to provide a quantitative output of a battery test. In FIG. 2B, the output  22  is in the form of a series of outputs  23 A,  23 B,  23 C and  23 D which can comprise LEDs.  
     [0016]FIG. 3 is a side cross-sectional view of battery  10  taken along the line labeled  3 — 3  in FIG. 2. As illustrated in FIG. 3, battery  10  is a storage battery such as a lead-acid battery and includes a number of electrochemical cells which are electrically connected in series by conductors  32 . This forms a string of cells  30  having one end electrically coupled to positive terminal  12  through conductor  34  and having the other end electrically coupled to negative terminal  14  through conductor  36 . As illustrated in FIG. 3, battery test module  16  is coupled to terminals  12  and  14  through two pairs of electrical connections which provide Kelvin connections  38  and  40 .  
     [0017] In operation, a user can test the condition of battery  10  using battery test module  16 . For example, through actuation of button  20  or another input device, a test can be performed on the battery. The results of the battery test are displayed on outputs  22  or  24 . In one embodiment, battery test module  16  monitors the battery and waits for a period when the battery is not in use or their is not excessive noise on the electrical system to which the battery is connected and then performs a test on the battery. The results of the battery test can be stored in memory and displayed on output  22  or  24 . In such an embodiment, an input such as input  20  is not required to activate the test. However, in such an embodiment, the circuitry within test module  16  could cause the battery to discharge over an extended period.  
     [0018] In the embodiment shown in FIG. 2B, battery test module  16  compares the voltage between terminals  12  and  14  to a number of different threshold voltages. Depending upon the voltage of battery  10 , an appropriate number of LEDs  23 A-D are illuminated on test module  16 . For example, each LED can correspond to a different threshold. These thresholds can be spaced as desired. The LEDs  23 A-D can also be of different colors. For example,  23 A can be a read LED while  23 D can be a green LED. In a slightly more complex embodiment, a load, such as a load resistance, in module  16  can be applied to battery  10  during or prior to a voltage measurement. The output of module  16  can be a function of the applied load.  
     [0019] In one embodiment, test module  16  illuminates outputs  23 A-D consecutively until the appropriate threshold is reached. To provide a more desirable user-interface, a small delay can be introduced between the illumination of the each LED. The timing can be as appropriate. The results of the battery test can be maintained on outputs  23 A-D for a desired length of time, preferably sufficiently long for a user to observe the test result. In one embodiment, the appropriate number of LEDs remain lit until the test is complete. In another embodiment, only a single LED is lit at a time. Of course, any number of LEDs and thresholds may be used. In other embodiments, additional information can be communicated to an operator by flashing LEDs providing a code or a warning.  
     [0020] The circuitry of the battery tester in the embodiment of FIG. 2B can be implemented using simple comparators and timing circuits as will be apparent to those skilled in the art. A more complex embodiment can include a small microprocessor. Typically, the circuitry of battery test module  16  is powered by storage battery  10 .  
     [0021]FIG. 4 shows a more detailed view of the electrical connections between battery test module  16  and the cells  30  of the battery  10 . Cells  30  are illustrated using the electrical symbol for a battery. Battery test module  16  is coupled to electrochemical cells  30  through Kelvin connections  38  and  40 .  
     [0022] A microprocessor in battery test module  16  can store information in memory  44  for later retrieval. For example, information regarding the history of battery usage and battery charging can be maintained in memory for later output. A special access code can be entered through user input  20  to cause the data to be output through output  22  or  24  or other output. In one embodiment, the output can be an audio output such as a series of tones or pre-recorded words. The input can comprise a special series of buttons or timing of pressing of buttons. Alternative inputs can also be provided such as an IR sensor, a vibration sensor, a magnetic switch, a proximity receiver which inductively couples to an external device or others. The output can be provided by energizing an LED in accordance with a digital code which could be read by an external device. Other types of outputs can be provided through an IR link, a proximity communication technique such as inductive coupling, etc. Other techniques include a serial or other hard wired output, RF and optical. Further, a battery test can be initiated based upon an input received through input  20  or  26 , using any of the above communication techniques, from a remote computer or other circuitry. This can also be used to initiate a data dump of information stored in memory. Inputs and outputs can also be provided to test module  16  by modulating data onto positive and negative terminals  12  and  14 . The data can be received or transmitted using transmit and receive circuitry in battery module  16 . Various modulation techniques are known in the art. In one embodiment, the modulation technique is selected such that it does not interfere with external circuitry to which battery  10  may be coupled.  
     [0023] The data recording and reporting technique allows a manufacturer to monitor usage of a battery. For example, the manufacturer could determine that the battery was left in an uncharged condition for an extended period, prior to sale, which caused damage to the battery. The data stored in memory can be keyed to date information if such information is maintained by a microprocessor in battery test module  16  such that various events in the life of the battery  18  can be linked to specific dates. Examples of other information which can be stored in memory  44  include the date of manufacture, battery ratings, battery serial number of other identification, distribution chain, etc.  
     [0024]FIG. 4 also illustrates another aspect of the present invention. In FIG. 4, element  10  can also illustrate a standby jumper or auxiliary system  10  which contains an internal battery  30 . Jumper cables or other output such as a cigarette lighter adapter, can couple to battery  30  and can be used to provide auxiliary power to an automotive vehicle. For example, such a system can be used to provide a brief charge to a vehicle or to start a vehicle having a dead battery. This can be used to “jump start” the vehicle. Such devices are known in the art and are typically small, portable devices which contain an internal battery. The internal battery can be, for example, a gel cell, a NICAD battery, a nickel metal hydrate battery or other type of battery. One problem with such auxiliary power systems is that the internal battery can fail without the knowledge of the user. When use of the of auxiliary power system is required, the battery may have failed. Further, the type of a failure may be one which is not easily detected in that the battery may provide a normal voltage output but is not capable of supplying a great deal of current for any period of time. With the present invention, system  10  can also include a test module  16  for testing battery  30 . In such an embodiment, a user could periodically test battery  30  to ensure it has not failed. Further, test module  16  can periodically test battery  30  and provide a warning indication such as a flashing light or a warning sound if battery  30  fails. In one aspect of the invention, any type of battery tester can be used to test such an auxiliary battery system.  
     [0025] The present invention can be implemented using any appropriate technique. One example is set forth in U.S. Pat. No. 6,172,505, issued Jan. 9, 2001, and entitled ELECTRONIC BATTERY TESTER which is incorporated herein by reference.  
     [0026] In one aspect, the battery test module determines battery condition based upon a dynamic parameter of the battery, that is a measurement of the battery which is made using a time varying forcing function F as shown in FIG. 4. The resultant signal S in FIG. 4 can be used to determine the dynamic parameter. Example dynamic parameters include dynamic conductance, resistance, impedance and admittance. In another example, single contacts are used to obtain a measurement across the battery.  
     [0027] Memory such as memory  44  within test module  16  can be used to store battery specific information such as the rating of battery  10 . The information can be loaded into permanent memory during manufacture. Thus, the user in not required to enter any information regarding the battery. This information can be used in performing the battery test and to provide a qualitative output to a user.  
     [0028] Output  22  can be any type of output including a visual output. Examples include bi or tri-color LEDs. The color along with a flashing condition of an LED can indicate test results such as good, bad, low charge, too low to test, or other conditions and determinations. A flashing LED can be used to indicate system noise, bad cell, or other conditions and determinations. When the user input  20  is used, the circuitry does not provide any drain on the battery except when activated. However, an input such a switch can increase cost and could allow a user to attempt a test at an inopportune time, such as during periods of high system noise.  
     [0029] In embodiments without input  20 , test module  16  can wait for a quiet time or other appropriate time to perform a test. The result can be stored in internal memory and periodically displayed on output  22 / 24  for a brief period. However, extended operation of the test module can drain the battery. In one embodiment, a start-up circuit can be triggered to ‘wake up’ the test module when the battery experiences a voltage increase such as that due to charging of the battery. The circuitry can then enter a ‘sleep’ mode based during period of non-charging in order to save power, for example, shortly after charging stops.  
     [0030] The battery test module of the present invention is preferable integral with the battery. For example, the module can be mounted to the housing such as to a top cover of the housing. In various embodiments, the module can be carried within the housing or within an isolated compartment in the housing. The Kelvin connections can couple to the battery terminals either through external or internal conductors.  
     [0031] Of course, the test circuitry and test module can be attached to the battery through any technique including for example, techniques that do not require any modifications to the battery container. For example, it can attach under bolts used on the battery post or can use a press fit or “trap” configuration to fit over the battery posts. This allows the circuitry to be optionally added to existing batteries.  
     [0032] Further, one aspect of the invention includes any tester that is integral with the battery or substantially permanently attached to the battery that provides an output related to a battery condition such as cold cranking amps (CCA) and/or uses Kelvin connections to couple to the battery.  
     [0033]FIG. 5 is a simplified circuit diagram of test module  16 . Module  16  is shown coupled to battery  10 . Module  16  operates in accordance with one embodiment of the present invention and determines the conductance (G BAT ) of battery  10  and the voltage potential (V BAT ) between terminals  12  and  14 . Module  16  includes current source  50 , differential amplifier  52 , analog-to-digital converter  54  and microprocessor  56 . Amplifier  52  is capacitively coupled to battery  10  through capacitors C 1  and C 2 . Amplifier  52  has an output connected to an input of analog-to-digital converter  54 . Microprocessor  56  is connected to system clock  58 , memory  60 , visual output  62  and analog-to-digital converter  54 . Microprocessor  56  is also capable of receiving an input from input device  66 . Further, an input/output (I/O) port  67  is provided.  
     [0034] In operation, current source  50  is controlled by microprocessor  56  and provides a current in the direction shown by the arrow in FIG. 5. In one embodiment, this is a square wave or a pulse. Differential amplifier  52  is connected to terminals  22  and  24  of battery  10  through capacitors C 1  and C 2 , respectively, and provides an output related to the voltage potential difference between terminals  12  and  14 . In a preferred embodiment, amplifier  52  has a high input impedance. Circuitry  16  includes differential amplifier  70  having inverting and noninverting inputs connected to terminals  24  and  22 , respectively. Amplifier  70  is connected to measure the open circuit potential voltage (V BAT ) of battery  10  between terminals  12  and  14 . The output of amplifier  70  is provided to analog-to-digital converter  54  such that the voltage across terminals  12  and  14  can be measured by microprocessor  56 .  
     [0035] Module  16  is connected to battery  10  through a four-point connection technique known as a Kelvin connection. This Kelvin connection allows current I to be injected into battery  10  through a first pair of terminals while the voltage V across the terminals  12  and  14  is measured by a second pair of connections. Because very little current flows through amplifier  52 , the voltage drop across the inputs to amplifier  52  is substantially identical to the voltage drop across terminals  12  and  14  of battery  12 . The output of differential amplifier  52  is converted to a digital format and is provided to microprocessor  56 . Microprocessor  56  operates at a frequency determined by system clock  58  and in accordance with programming instructions stored in memory  60 .  
     [0036] Microprocessor  56  determines the conductance of battery  10  by applying a current pulse I using current source  50 . The microprocessor determines the change in battery voltage due to the current pulse I using amplifier  52  and analog-to-digital converter  54 . The value of current I generated by current source  50  is known and is stored in memory  60 . In one embodiment, current I is obtained by applying a load to battery  10 . Microprocessor  56  calculates the conductance of battery  10  using the following equation:  
             Conductance   =       G   BAT     =         Δ                 I       Δ                 V          1               Equation  1                       
 
     [0037] where ΔI is the change in current flowing through battery  10  due to current source  50  and ΔV is the change in battery voltage due to applied current ΔI. A temperature sensor  62  can be thermally coupled to battery  10  and used to compensate battery measurements. Temperature readings can be stored in memory  60  for later retrieval.  
     [0038]FIG. 6 is a simple diagram for the embodiment of module  16  shown in FIG. 2B. A comparator  90  can periodically compare a voltage measurement to a plurality of reference levels and responsively energize LEDs  23 A-D to provide an indication of the condition of battery  10 . This display can be provided or be activated by a switch or other condition. Any of the various features set forth in the Figures and discussion can be used in any appropriate combination and should not be limited to the specific examples shown.  
     [0039] 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.