Abstract:
A battery includes a battery tester including a display that is disposed around a substantial portion of the circumference of the battery. Also describe is a battery operated electronic device including a case that houses electronic components that comprise the electronic device, said case including a door that opens up to a battery compartment, with the door having at least a transparent window portion in the door.

Description:
BACKGROUND 
     This invention relates to battery testers that are incorporated in, or on battery cell labels or packaging. 
     Know types of batter testers that are placed on batteries are so called “thermochromic” types. In a thermochromic battery tester, a thermochromic display is placed as a narrow, elongated region of a label. The display is typically a single narrow and elongated region. The thermochromic battery tester operates by a consumer depressing a manual switch. Once the switch is depressed the consumer connects an anode of the battery to a cathode of the battery and can read the relative power remaining in the battery. The connection goes through a silver conductor that has a variable width so that the resistance of the conductor also varies along its length. As current travels through the silver conductor, the current generates heat that changes the color of a thermochromic ink in the thermochromic display over the silver conductor. The thermochromic display is arranged as a gauge to indicate the relative capacity of the battery. The higher the current the more heat is generated and the more the gauge will change to indicate that the battery is good. 
     In order to test the battery the display needs to be aligned so that the consumer can read it. Also, sometimes the switch can be hard for people to depress and it becomes difficult to tell whether the tester worked or not or whether the battery is good or bad. This can be confusing to a consumer. Depressing the switch makes a direct relatively high conductance connection between the anode and cathode of the cell which can draw significant power and reduce battery lifetime. 
     SUMMARY 
     According to an aspect of the invention, a battery includes a battery tester including a display that is disposed around a substantial portion of the circumference of the battery. 
     According to an additional aspect of the invention, a battery operated electronic device includes a case that houses electronic components that comprise the electronic device, said case including a door that opens up to a battery compartment, with the door having at least a transparent window portion in the door. 
     One or more of the following advantages may be provided from aspects of the invention. 
     The battery tester display is incorporated over an entire circumference of a battery label or cover. A consumer does not have to hold the battery in one orientation to look at the display. The display is visible from any orientation. An additional advantage is that if the battery tester is a passive tester, not requiring the consumer to close a manual switch, the consumer can merely look at the battery from any angle and tell whether the battery is good or bad condition or how much capacity might be left in the battery. A still further advantage is that the consumer can look at the battery in its original packaging to tell whether the battery is good or bad condition or how much capacity might be left in the battery. 
     A still further advantage is that when the battery is disposed in an electronic device, and if the electronic device is built with a transparent window exposing the battery compartment, the capacity left in the battery can be determined by merely looking at the battery through the window. Thus, the consumer can determine whether the battery is good or bad condition or how much capacity might be left in the battery without removing the battery from the electronic device. This is a useful advantage particular since it allows the battery to be examined under a load condition and obviates the need to remove the battery from devices where the battery might be somewhat difficult to reach. The consumer can know immediately if the device is bad or if the batteries are bad. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross-sectional view of an M-I-M diode structure. 
     FIG. 1A is a blowup view taken along line  1 A— 1 A of a portion of FIG.  1 . 
     FIG. 2 is a cross-sectional view of an alternative M-I-M diode structure. 
     FIG. 2A is a blowup view taken along line  2 A— 2 A of a a portion of FIG.  2 . 
     FIG. 3 is cross-sectional view of another alternative M-I-M diode structure. 
     FIG. 4 is a flow chart of a process to manufacture the device of FIG.  1 . 
     FIGS. 5A-5D are plots of voltage vs. current showing typical switching characteristics of M-I-M diode devices of FIGS. 1-4. 
     FIG. 6 is a schematic diagram of a multiple nonlinear element segmented display battery tester. 
     FIG. 7 is a schematic diagram of a multiple resistor, variable display battery tester. 
     FIG. 8 is a diagrammatical, perspective view of a construction example for a multiple nonlinear element battery tester of FIG.  6 . 
     FIG. 9 is a diagrammatical view of a construction example for the multiple nonlinear element battery tester of FIG.  6 . 
     FIG. 10 is a diagrammatical view of a construction example for the multiple resistor battery tester of FIG.  7 . 
     FIG. 11 is a perspective view of a battery cell having a segmented display battery tester disposed about a circumference of the battery. 
     FIG. 12 is a perspective view of a battery cell having a variable display battery tester disposed about a circumference of the battery. 
     FIG. 13, is a diagrammatical view of an alternative arrangement for a battery having a segmented battery tester display. 
     FIG. 14 is a diagrammatical view of a battery operated device having a battery compartment. 
     FIG. 15 is a schematic view of a on/off battery tester incorporating a voltage controlled display. 
    
    
     DESCRIPTION 
     Referring now to FIG. 1, a metal-insulator-metal diode  10  is shown. The metal-insulator-metal diode  10  includes a first electrode  12 , e.g., a copper foil substrate or another conductive material such as carbon or gold or other conductive materials such as chromium, tungsten, molybdenum, or other conductive materials such as metal particles dispersed in a polymer binder such as a conductive ink. The metal-insulator-metal diode  10  further includes a composite metal-insulator layer  14  comprised of metal particles  20  suspended in a dielectric binding layer  22 . As shown in FIG. 1A, the metal particles  20  have an intrinsic oxide layer  20   a  that covers the surface of the particles  20 . One preferred metal is tantalum that readily forms an intrinsic, stable and generally uniform intrinsic oxide layer  20   a . Other metals can be used such as niobium. These other metals should form oxides that are self-limiting, stable, and having a suitable dielectric constant for the application. One reason that tantalum is preferred is that the intrinsic oxide layer forms readily on tantalum upon its exposure to air. 
     Disposed on the composite metal-insulating layer  14  is a second electrode  16  also comprised of e.g., copper or another conductive materials such as a carbon, chromium, tungsten, molybdenum, or gold or other conductive materials. The second electrode is preferably disposed directly on the layer  12  to be in contact with the intrinsic oxide layer  20   a  on the particles  20 . The second electrode also can be a composite layer including the conductive materials and a binder. By varying the conductivity of the electrode layer  16 , the electrical characteristics of the device  10  can be changed. Specifically, the I-V characteristic curve can be made sharper to obtain a steeper on/off characteristic. That is, the higher the electrical conductivity, the sharper the curve. 
     As will be described below in FIGS. 5A-5D, the M-I-M device has a symmetrical current-voltage (I-V) characteristic curve exhibiting diode-like properties. The device also can be made to have lower switching voltages than other approaches, e.g., less than 10 volts and more specifically less than 1 volt to about 0.5 volts but with the same symmetrical properties. By varying the ratio of the tantalum to the binder and also the thickness of the tantalum-binder layer enables shifting of the I-V characteristic curve for the same material up or down within a range of plus/minus 50% or more. 
     The switching voltage of the device  10  can be more consistent from device to device. This may occur due in part to the more consistent oxide layer thickness and quality of the intrinsically formed oxide. The thickness of the tantalum oxide layer  20   a  does not vary widely compared to thermal annealing or anodized oxide layers. It is believed that the intrinsic layer  20   a  also has a substantially uniform thickness from tantalum particle  20  to tantalum particle  20  that is on the order of monolayers of thickness. Characteristics of the tantalum particles are that the powder has a particle size in a range less than 0.5 microns up to about 10&#39;s of microns. The printed layer  14  can have a thickness less than 0.5 mils up to 8-10 mils. Other particle sizes and thicknesses could be used herein. 
     Referring now to FIG. 2, another embodiment  10 ′ of the diode includes a layer  14 ′ comprising inert particles  24  (as shown in FIG. 2A) of another dielectric material such as particles  24  of titanium dioxide TiO 2  or magnesium carbonate MgCO 3  dispersed within the polymer binder  22  and the tantalum particles  20  having an oxide layer  20   a . In this embodiment, a portion (e.g., 0% to 75%) of the tantalum particles  20  are replaced with inert dielectric material particles  24  such as the titanium dioxide or magnesium carbonate. The tantalum particles  20  can optionally have an annealed oxide or other type of oxide layer disposed about the tantalum although, the intrinsic oxide layer  20   a  a alone is preferred. 
     The addition of dielectric particles of e.g., titanium dioxide solids to the polymer binder  22  and the tantalum particles  20  can improve printing of the layer  14 ′, enabling use of lower amounts of tantalum particles while still maintaining a high solids content that would exhibit good diode properties. This would be particularly desirable with very thin layers of the metal/insulating material layer to avoid shorting of the two electrodes  12  and  16  through the layer  14 ′. Including an inert material reduces the probability of shorting and provides a more consistent film/coating. 
     Moreover, at sufficiently low concentrations of tantalum, devices may be provided with higher switching voltages. It is anticipated that rather than using the oxide layer around the tantalum particles to act as the insulator, i.e., the potential barrier that electrons need to exceed in order to cause conduction, the barrier would be governed by the dielectric properties of the inert material, e.g., the titanium dioxide and the binder at the lower concentrations of tantalum. 
     Referring now to FIG. 3, another embodiment  10 ″ of the diode has the first electrode  12  and the metal-insulating layer  14  or  14 ′ on the first electrode. This structure  10 ″ may give similar diode properties when a connection  28  is made to the metal-insulating layer  14  or  14 ′. By eliminating the second electrode, the device  10 ″ can have fewer layers, changing the fabrication process without substantially altering the characteristics of the metal insulator layer. 
     Referring now to FIG. 4, the device of FIG,  1  can be prepared as follows: The process  30  includes mixing  32  tantalum powder that is 99.97% pure, having the intrinsic oxide layer and having a particle size less than e.g., 5 microns, with a polymer binder such as Acheson, Electrodag No. 23DD146A, or Acheson SS24686, a more thixotropic material. Both polymer binders are available from Acheson, Port Huron, Mich. Other binders can be used with the tantalum to form a tantalum ink. The binders should be electrically insulating, stable with tantalum or the other metal used and preferably have an relatively high e.g., 15% to 35% or so solids content. The tantalum can be in a range of 100% to 39% of the total weight of the binder. Other ranges could be used. The tantalum particles and binder are mixed well to produce the tantalum ink. The tantalum ink is printed  34  on the first electrode e.g., a copper foil substrate or on other conductive material. The layer is printed, for example, by either draw down bars, screen printing, flexo or gravure printing techniques. The layer is dried  36 , e.g., in an oven at 120° C. for 15-20 minutes. A second conductive layer such as chromium in the form of chromium particles mixed in a binder material is printed  38  on the tantalum binder layer. This chromium layer is also dried  40  at e.g., at 120° C. for 15-20 minutes producing the device  10 . Thereafter, the device  10  can be tested  42 . 
     Alternative conductive layers or metals such as copper, tungsten, molybdenum, carbon and so forth can be used for the first and/or second electrode. The conductivity of this layer can be varied by changing relative concentrations of conductive material to binder. Exemplary ranges for conductive material are 30% to 39%. By varying the conductivity of this layer, the shape of the current-voltage characteristic curve can be varied, making it a little sharper producing a diode having a steeper on/off response. 
     Processing is simplified because the tantalum particles used have an intrinsic oxide layer  20   a . There is no need to thermally anneal or otherwise thermally preprocess the tantalum powder. The intrinsic oxide coating is very consistent in thickness and quality. This tends to produce very consistent metal-insulator layer materials and hence diodes with switching voltages having relatively low standard deviations over a series of diodes. 
     Another advantage is that since there is no need to thermally anneal the tantalum powder, the properties of the ink can be adjusted to achieve various diode properties to fit different applications. Ink formulation may be an easier process to control than thermal processing of the tantalum. 
     This device could also be referred to as a varistor, i.e., a thin printed varistor. This M-I-M structure is good for applications that need a nonlinear element that operates at low voltages and perhaps low current that can be printed rather than using semiconductor deposition techniques. 
     Referring now to FIGS. 5A-5D plots of voltage vs. current showing typical switching characteristics of M-I-M diode devices of FIGS. 1-5 are shown. As shown in FIG. 5A, a current voltage characteristic curve  44  for a M-I-M diode device exhibits a switching voltage at 100 na. (nano-amperes) of approximately 1.8 volts, with an on/off ratio that is calculated to be about 33. The current voltage characteristic curve  44  was obtained using a Hewlett Packard semiconductor analyzer, Model No. 4155B. 
     This device used a tantalum layer that was prepared by mixing 5 grams of tantalum particles obtained from Alfa Aesar, Ward Hill, Mass. having a particle diameter of less than 2 microns, with 20 grams of Electrodag 23DD146A polymer having a 25% solid versus 75% volatile compound composition. The ink was coated onto a conductive surface of copper foil using a 15 mil cutout i.e., to produce a layer having a wet thickness of 15 mils. The sample was dried in an oven at 120° C. for 20 minutes. The ink for the second layer of the diode was prepared by mixing 5 grams of chromium powder with a particle size of less than 5 microns as received from Alfa Aesar with 4 grams of Electrodag 23DD146A and was coated on top of the tantalum ink layer using a 5 mil cutout. This coating was dried for 20 minutes at 120° C. 
     As shown in FIG. 5B, the M-I-M diodes can exhibit different switching voltages based upon different “P:B” ratios, that is, different ratios of metal (e.g., tantalum) particles to binder. As shown in FIG. 5B, for the same thickness of 15 mils, with P:B ratios of 5, 2, and 1, devices exhibit switching voltages of approximately 9 volts (curve  45   a ), 5.3 volts (curve  45   b ) and 3.8 volts (curve  45   c ) at 100 nano amperes. 
     As also shown in FIG. 5C, varying the wet thickness of the tantalum layer can also produce varying switching voltages. With a tantalum layer having a tantalum to binder ratio (P:B) of 8:1, a M-I-M diode having a 15 mil thick tantalum layer would exhibit a switching voltage of approximately 9 volts (curve  46   a ), a 10 mil thick layer would provide a M-I-M diode with a switching voltage of approximately 7.8 volts (curve  46   b ), and a 5 mil thick layer would provide a M-I-M diode with a switching voltage of approximately 4.6 volts (curve  46   b ). Each of the switching voltages are measured at 100 nano amperes. 
     Referring now to FIG. 5D, addition of magnesium carbonate to the tantalum layer can produce M-I-M diodes that have consistently high on/off ratios with minimal impact on switching voltage. As shown in FIG. 5D, as the amount of magnesium carbonate is increased, the switching voltage characteristic becomes steeper. The curve  46   a  shows the switching characteristic for a 100% tantalum layer having a P:B ratio of 1:1 that exhibits a switching voltage of 1.8 volts. Curves  47   b - 47   d  illustrate that as the amount of magnesium carbonate increases, the switching characteristic becomes steeper therefore indicating a better on/off ratio. 
     Referring now to FIG. 6, a multiple, nonlinear element battery tester  50  is shown connected to a battery  51 . The multiple, nonlinear element battery tester  50  is comprised of a plurality of individual, nonlinear element battery testers  52   a - 52   e  coupled to provide a parallel circuit. Each of the individual, nonlinear element battery tester circuits  52   a - 52   e  include a non-linear element such as a M-I-M diode  54   a - 54   e , respectively, and a film resistor  56   a - 56   e  respectively. The battery tester  50  includes a voltage divider provided by two resistors,  58  and  60  coupled in parallel with the plurality of individual non-linear element battery testers  52   a - 52   e . Each of the individual non-linear element battery testers  52   a - 52   e  includes a corresponding one of a plurality of display devices  62   a - 62   e  disposed between an electrode  55  (potential V f ), and a common connection of the respective parallel circuits  52   a - 52   e  of the non-linear elements, i.e., M-I-M diodes  54   a - 54   e  and the film resistor  56   a - 56   e.    
     The display devices  62   a - 62   e  are of a ultra-low current, low voltage, voltage controlled display type. One type of display devices  62   a - 62   e  are an electrophoretic display device such as described in “All Printed Bistable Reflective Displays: Printable Electrophoretic Ink and All Printed Metal-Insulator-Metal Diodes” Massachusetts Institute of Technology June 1998 and provided by E-INK, Inc. Cambridge, Mass., that are modified to include low switching voltage devices as described above in FIGS. 1-5D. 
     This type of display is based on so called “electronic inks”, e.g., electrophoretic materials that change their properties e.g., color based on an applied voltage. Using electrophoretic materials such as electronic ink, a flat panel display can be printed on a substrate material. These displays draw very little current and hence dissipate very little power. Any voltage sensitive material could be used as the display. Another material that has been described in “The Reinvention of Paper”, Scientific American, September 1996, called Gyricon which is also voltage sensitive. The display needs to operate at voltages that are within the range of the voltage of battery. 
     The non-linear devices  54   a - 54   e  can be the M-I-M diode  10  described above in conjunction with FIGS.  1 - 5 A- 5 D. 
     The multiple, nonlinear element battery tester  50  has five different diodes, in five parallel paths. If the diodes are constructed to switch at a different voltage, the displays would change state at different voltages producing a segmentation of the display or a gauge effect that would indicate charge status of the battery. 
     The multiple, nonlinear element battery tester  50  has one terminal of each of the displays  62   a - 62   e  coupled to a common voltage potential labeled as V f . The voltage potential V f  is derived from a point between the two resistors,  58 ,  60 , and if resistors  58  and  60  are equal, provides Vf at one-half of the voltage of the cell. The different parallel segments  52   a - 52   e  have a value of voltage respectively, at points A-E where the magnitude of the voltage is set by the diodes  54   a - 54   e  and the resistor elements  56   a - 56   e . The different parallel segments  52   a - 52   e  can be set to have monotonically increasing or decreasing values of voltage at points A-E. For example, for a 9 volt battery, one diode  54   a  could be selected to switch at 8 volts, diode  54   b  could be selected to switch at 7 volts, diode  54   c  could be selected to switch at 6 volts, and so on, so that as the voltage of the battery drops, different segments of the displays  62   a - 62   e  turn off. 
     The diodes  54   a - 54   e  can be set to switch at different voltages that would either turn “on” or turn “off” the display, i.e., change from one color to another color depending on how the display is connected to the circuit. The number of segments is only limited by how well the diodes can differentiate different voltages. In the 9 volt example, a one volt difference was used. But if the diodes are fabricated to produce exactly {fraction (1/10)} of a volt difference the battery tester can have {fraction (1/10)} of a volt switching difference and the battery tester can be expanded out to 15 or 60 segments or more segments. 
     The current drawn from the battery can be selected to depend on the values of resistance of the voltage divider of resistors  58  and  60 . The display devices  62   a - 62   e  draw very little current. 
     Since diodes  54   a - 54   e  are non-linear, at some point as diodes  54   a - 54   e  switch they will cause the voltage at electrode  55  to become negative with respect to the voltage of respective ones of the electrode coupled to points A-E. This would cause corresponding flips or changes in the polarity on the displays  62   a - 62   e  causing the displays  62   a - 62   e  to change color indicating that the battery is loosing charge. When the last one of the displays e.g., 62 e  changes color it could indicate that the battery  51  is no longer within some defined specification. 
     Referring now to FIG. 7, an alternate embodiment  50 ′ of a multiple, nonlinear element battery tester  50  is shown connected to a battery  51 . In this battery tester  50 ′, segmentation i.e., a gauge effect, is provided by using different resistors with a common, segmented display device  78 . The battery tester  50 ′ includes a parallel circuit. On one side of the parallel circuit is a nonlinear element, e.g., a M-I-M diode  72  and resistor  74 . On the other side, rather than just having the two resistor elements to split the current, as the battery tester  50 ′ of FIG. 1, the battery tester  50 ′ includes a plurality of resistors e.g., five,  76   a - 76   e . The plurality of resistors  76   a - 76   e  are coupled to corresponding electrodes  76   a - 76   d  of a display  78  that has a second electrode  80  coupled at the connection of the non-linear element  72  with the resistor  74  which is at a potential E. The voltage at, any point A-D along the display  78  is equal to the sum of the resistance up to that point divided by the total resistance, as shown below for Equations 1-4.                V   a     =       V   battery            R   1         R   1     +     R   2     +     R   3     +     R   4     +     R   5                   Equation                 1                 V   b     =         V   battery          R   1       +       R   2         R   1     +     R   2     +     R   3     +     R   4     +     R   5                   Equation                 2                 V   c     =         V   battery          R   1       +     R   2     +       R   3         R   1     +     R   2     +     R   3     +     R   4     +     R   5                   Equation                 3                 V   d     =         V   battery          R   1       +     R   2     +     R   3     +       R   4         R   1     +     R   2     +     R   3     +     R   4     +     R   5                   Equation                 4                                
     The voltage V E  at point E is relatively constant throughout the life of the cell and the voltages V A , V B , V C  and V D  will vary with respect to the voltage V E  at point E. There will be different points at which the values of the voltages at points A, B, C and D are positive with respect to point E or negative. When there is a polarity change there is a corresponding change color of the display. The difference in the values of resistors  76   a-   76   e  can be easily varied by printing different widths of conductive material. 
     Preferably, all of the resistors  76   a - 76   e  are printed with a transparent conductive material such as ITO (indium tin oxide) and suspended in a polymer binder material. The conductivity of the printed layers can be varied by changing the amount of ITO dispersed in the polymer binder with low levels of ITO producing films of high resistance. A circuit with an overall resistance of 15 meg-ohms between anode and cathode would produce a current draw of 100 nano-amps (na). This relatively low current draw would have a impact on cell capacity of only about ½ percent. 
     Referring now to FIGS. 8 and 9, an example of the battery tester  50  (FIG. 6) is shown. A transparent conductor  94 , e.g, a material such as an ITO (indium tin oxide) ink or a transparent coating used for electrostatic dissipation is printed on the cell or label of the battery  51 . Examples of the material of the transparent conductor, include an electrostatic coating. The transparent conductor  94  need not carry a high current because the displays  62   a - 62   e  (FIG. 1) are voltage sensitive displays. The transparent conductor is merely a current carrying material. The transparent conductor  94  is attached to resistors  58 ,  60  which attach to the anode or the cathode, so the transparent conductor  94  is attached between the anode and the cathode. The attachment of resistors  58 ,  60  to the anode and the cathode of battery  51  can be provided by glueing, crimping or other arrangements. 
     Resistors  58 - 60  may be formed from strips of material having different widths or thicknesses to provide different resistances. On top of the transparent conductor  94 , the display is printed. This display could be the electrophoretic ink display mentioned above or it could be a Gyricon based display or any other voltage sensitive material that produces a change in color by varying an applied voltage. 
     The display includes an electrophoretic ink material  96  that is printed on the transparent conductor  94 . On top of the electrophoretic ink material  96 , a first conductor  98  of the display is printed. This conductor  98  couples one side of the display to one of the poles of the battery, either the anode or the cathode, depending on how the display is to be initially switched. This conductor  98  is also printed in segments and is coupled to resistors  56   a - 56   d  (FIG. 6, only four used in this example). If the conductor  98  is printed as one solid conductor, the conductor would carry a uniform voltage. Printing the conductor in sections gives a segmentation, e.g., gauge effect. 
     The diodes  54   a - 54   d  (FIG. 6, only four used in this example) are printed by depositing a tantalum layer segments  100  having tantalum particles with an intrinsic oxide coating in a dielectric binder as described above. The intrinsic oxide has a sufficient thickness to provide M-I-M diodes. In order to vary the characteristics of the parallel paths, these segments can be at different thicknesses to give different diode properties. This provides a different switching voltage for each diode. 
     A second electrode  102  such as a chromium layer is printed on top of the tantalum layer. The second electrode  102  is surrounded by an optional dielectric coating  104  to insure that short circuits are avoided. A second conductor  106  is printed on top of the second electrode  102  to connect all the chromium layers together. The second conductor  106  is connected to the opposite pole of the battery from the first conductor  94 , either anode or cathode depending on which pole the first conductor  98 . 
     Referring now to FIG. 10, an example of the multiple resistor battery tester  50 ′ is shown. The battery tester  50 ′ is laid-out very similar to the battery tester  50 . A transparent conductor  110  is printed in different sections  110   a - 110   d  to provide segmentation i.e., the battery charge gauge. The transparent conductor  110  is printed to include a wedge-shaped conductor portion  110   e  to produce resistors  76   a - 76   e . The wedge-shape conductor portion  110   e  has a resistance characteristic that varies along the conductor length so that at the narrower end it has a higher resistance while at the wider end it has a lower resistance. The conductor portion  110   e  could also be a single width where the resistance at any point in the conductor would depend on how far that point was from one pole of the battery. Other arrangements are possible. 
     The wedge-shaped conductor portion  110   e  is connected to both the anode and the cathode of battery  51  such as by glueing or crimping or other arrangements. On top of the transparent conductor  110  is printed the display material  112 , e.g., the E-Ink or Gyricon or other voltage sensitive material. Over the display material  112  another conductor  114  is printed. One end of the conductor  114  is connected via resistor  115  to one of the poles of the cells, either the anode or the cathode. On top of that conductor, a tantalum oxide/tantalum metal layer  116  is printed and on top of tantalum oxide/tantalum metal layer  116  the second electrode  118  e.g., a chromium layer is printed. The second electrode  118  is connected to the opposite pole of the cell. 
     Since the battery tester  50  or  50 ′ is a printed device, the non-linear device can be provided with carbon ink based electrodes as described above. The resistors can also be carbon-based with a dielectric filler to reduce the conductivity of the resistors making them more resistive. Ideally the entire battery tester  50  should have a very high total resistance, e.g., on the order of 15 meg-ohms. For a 1.5 volt cell that would provide a tester  50  or  50  ′ that draws 100 nano-amps which is a low enough current level to have a minimum impact on the lifetime of the battery. For example, for a “double A” cell with a 7 year lifetime, a 100 nano ampere draw would consume only about 0.5 percent of the battery&#39;s capacity. 
     Typical thicknesses for the layers in the battery testers can be as follows: The transparent conductor could have a thickness between 0.1 to 0.2 mils; the display medium 1.0 mil; the electrode layers 0.1-0.2 mils; tantalum layer for the M-I-M diode 0.5-1.0 mils and various dielectric layers 0.2-0.5 mils. 
     Other thicknesses could alternatively be used. 
     Referring now to FIG. 11, a battery  51 ′ having a battery tester  150  with a segmented display is shown. The battery tester  150  includes a first plurality of segments  154   a - 154   g  disposed in a second plurality of columns 156 a - 156   g  along the length of the battery  51 ′. The battery tester  150  can be provided by using one tester that is disposed around the battery  51 ′. In the battery tester  150 , the battery tester  150  is turned sideways around the battery  51 ′. The battery tester  150  is arranged such that successive ones of the segments  154   a - 154   g  turn on or off at different voltage levels to give an indication of the power remaining in the battery  51 ′. 
     Thus, as an example, for a given condition of the battery  51 ′, the battery tester  150  can have all segments  154   a  and  154   b  in all columns  156   a - 156   g  turn on to indicate that the battery has spent “two sevenths” ({fraction (2/7)}) of its useful life. The battery tester  150  is incorporated over the entire circumference of the battery  51 ′. Therefore, a consumer does not have to hold the battery in one orientation to look at the display, since the display is visible from any orientation. 
     Referring now to FIG. 12, a battery  51 ″ including a battery tester  162  with a variable display is shown. The battery tester  162  is comprised of individual battery testers  164  that are printed in columns  166   a - 166   g  that are disposed around the circumference of the battery  51 ″. Thus, unlike the battery tester  150  (FIG.  11 ), i.e., a tester that is expanded all around the cell, the battery tester  162  is comprised of a series of battery testers  164  arranged in vertical columns  166   a - 166   g  along the height of the battery  51 ″. 
     Referring to FIG. 13, an alternative arrangement  170  for a battery  51 ′ having a segmented battery tester display  172  is shown. The segmented battery tester display  172  includes a plurality of segments  174   a - 174   d  disposed in a plurality of rows  176   a - 176   d  in a band around an upper portion of the battery  51 ′. The segmented battery tester display  172  can be provided by using one segmented tester that is disposed around the battery  51 ′. In the segmented battery tester display  172 , the segmented battery tester display  172  is turned sideways around the battery  51 ′. The segmented battery tester display  172  is arranged such that successive ones of the segments  174   a - 174   d  turn off at different voltage levels to give an indication of the power remaining in the battery  51 ′. This arrangement could be used to replace a gold band found around an upper circumference portion of batteries from Duracell® Gillette, Inc. Boston Mass. As the battery capacity is consumed, the gold band could change to a different color or disappear to indicate remaining capacity. 
     Referring now to FIG. 14, a electronic device  180  includes a body  182  having a battery compartment  184  with a door  186 . A battery, as shown can be placed in the battery compartment. The door  186  has a transparent window  188 , through which a consumer can see the battery  51 ′ or  11 ″ and read the display of the battery tester  150  or  162  for those testers that can be considered as passive testers, i.e., those that do not require any action on the part of the consumer to activate  62  (FIG. 6) or  78  (FIG.  7 ). The electronic device can be any type of consumer device including without limitation, a calculator, cellular telephone, toy, radio and so forth. The transparent window could be part of the door or indeed could be the entire door. 
     Alternatively, the battery tester  150  (FIG. 6) or the battery tester  162  (FIG. 7) can be implemented with active battery testers i.e., those that require some consumer action such as manually closing a switch to electrically connect the tester to the battery electrode(s). In order to allow for inspection within the battery compartment of an electronic device, the compartment can be provided with an external lever or linkage (not shown) that would permit the user to test the battery having a manual type of tester. 
     While the battery tester displays  150  and  162  were described as being disposed around the entire circumference, other arrangements are possible. For example, they could be disposed in quadrants or even about ⅔ to ¾ about the entire circumference of a battery. Moreover, to accommodate other information on the label they do not have to extend over the entire or substantially entire length or circumference of the battery, but could be a portion of the length or circumference. 
     Moreover, other types of tester could be used. For example, rather than using a tester that gives a gauge effect, a tester that merely gives a good or bad indication could also be used, as will now be described. 
     Referring now to FIG. 15, a good/bad indicator battery tester  200  is coupled to a battery  51 . The battery tester  200  includes a parallel circuit including a display device  206  disposed between two electrodes  202 ,  204  that are in parallel. 
     Electrode  202  is connected to the circuit  200  at a voltage divider provided by two resistors,  208  and  210 . Electrode  204  is connected to the other side of the parallel circuit. The other side of the parallel circuit has a nonlinear element, i.e., a switch  212  and a third resistor  214 . The display device  206  is an ultra-low current, voltage controlled type of display. The non-linear device  212  is a M-I-M diode as described above. 
     The voltage potential at terminal  202  will always have, half of the battery cell voltage across it if the value of resistor  208  equals the value of resistor  20 . The potential of the electrode  204  is determined by voltage across the nonlinear element  212  and resistor  214 . The voltage at terminal  202  will start at a known value depending on the values of resistors  208 ,  210  and  214 . As current is drawn from the battery due to use or leakage, the voltage of electrode  202  will vary with respect to the voltage at electrode  204 . Since element  212  is non linear, at some point it will switch causing the voltage at electrode  202  to become negative with respect to the voltage of electrode  214 . When the non-linear element switches, this would flip the polarity on the display causing the display to change color indicating that the battery is no longer within some defined specification. The display can be wired into the circuit so that either color of the display can indicate that the battery is no longer within some defined specification. In either event the battery tester works on the principle that the display exhibits a change in color when there is a change in the status i.e., good to bad of the battery cells. 
     Since the battery tester  200  is a printed device, the non-linear device can be provided with carbon ink based electrodes, as described in the above pending application. The resistors can also be carbon based and include a filler to reduce the conductivity of the resistors to make them more resistive. Ideally the entire battery tester  200  should have a very high total resistance, e.g., on the order of 15 meg-ohms. For a 1.5 volt cell that would provide a tester  200  that draws 100 nano-amps (na) of current which is a low enough current level to have a minimum impact on the lifetime of the battery. For example, a “double A” cell with a 7 year lifetime, a 100 na draw would consume only about 0.5 percent of the battery&#39;s capacity. 
     Other Embodiments 
     It is to be understood that while the invention has been described in conjunction with the detailed description thereof, the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the scope of the following claims.