Batteries are generally stored for various periods of time before being put into use. The batteries can be stored by the seller and frequently when purchased they are again stored by the buyer prior to being put to use. It is therefore desired to have some sort of testing means for determining if a battery has been partially discharged and thus may not have sufficient charge to operate a desired device. Initially, separate battery testers were developed which could measure the strength remaining in the battery. Recently battery testers have been developed that either are included in the battery package or assembled in the label secured to the battery. The testers generally indicate the capacity remaining in the battery.
U.S. Pat. No. 4,702,564 discloses a device for testing a battery, particularly a small, portable battery, comprising a flexible, transparent substrate on which is deposited a narrow band of a black light-absorbing material. A conductive material, which may taper outwardly in opposite directions from a central point to a pair of outer terminals, is then deposited atop the substrate on the same side of the substrate as the absorber layer or on the opposite side of the substrate as the absorber layer. A layer of a cholesteric liquid crystal material is then deposited on the substrate on the opposite side from the black absorber layer or over the absorber layer. The conductive material is an epoxy cement-based conductor, preferably silver, printed or painted directly on the substrate. An indicator scale is located along sections of the conductive material. To test a dry cell battery, the terminal ends of the conductive material are placed in contact with the battery terminals, causing a current to flow which heats the conductive material, the heat generated being the most intense at the central point and radiating outwardly. The heat is transferred through the thin substrate to the liquid crystal layer which results in a color change in the liquid crystal. The traverse of the color change along the length of the indicator scale, outwardly from the center point, is proportional to the current or voltage output or the condition of the battery to be tested and can be read on the indicator scale which is calibrated accordingly. The tester also includes means for determining the amp-hours or life of a battery.
U.S. Pat. No. 5,015,544 discloses a battery strength indicating and switch means on a battery which is coupled across the terminals of the battery and which is provided with an indicating means to indicate the strength of the battery and in addition, the battery strength indicating means is also provided with an in-line switch which can easily be depressed to complete the circuit so as to place the indicator means across the terminals of the cell and display the charge of the battery.
U.S. Pat. No. 5,059,895 discloses a battery voltmeter comprising:
(A) a dielectric layer; PA1 (B) a conductive layer above or below one of the surfaces of the dielectric layer; and PA1 (C) a temperature sensitive color indicator layer in thermal contact with the conductive layer, PA1 (i) a film base; PA1 (ii) an electrically conductive layer disposed on one side of the film base, PA1 (iii) a protective layer disposed on the electrically conductive layer, and PA1 (iv) a thermochromic layer disposed on the other side of the film base.
characterized in that the conductive layer has (i) thermal insulating means under one of its surfaces and (ii) sufficient heat generating capacity to affect a change in the temperature sensitive color indicator layer. The voltmeter can be integrated into a label and attached directly to a battery.
U.S. Pat. No. 4,835,475 discloses an apparatus for indicating the electromotive force of a dry battery which comprises:
Japanese Kokai Patent, SHO 63-213256 discloses a battery equipped with a color timer in which a sensor that changes color with time is placed on a battery so that capacity consumed can be displayed.
In the NASA Technical Note NASA TN D-5773, National Aeronautics and Space Administration, Washington, D.C. July 1970, an article by Richard S. Secunde and Arthur G. Birchenough discloses a mercury electrochemical coulomer as a battery charge indicator. Specifically, use of a mercury-column electrochemical coulometer is discussed as a means of indicating the state of charge of secondary batteries. A state-of-charge indicator was designed, built in breadboard form, and tested. The coulometer is the element which integrates the ampere-hours into and out of the battery. The state of charge then is the difference between the known fully charged battery capacity and the net ampere-hours removed. The general nonlinear charge-discharge characteristics of a battery were matched through the use of operational-amplifier techniques. The results of electrical and temperature tests on the breadboard of the indicator demonstrate that the mercury-column coulometer is a feasible device around which a battery state-of-charge indicator suitable for space power systems, or other uses, might be built.
Other types of label charge indicating devices have been disclosed in the art.
An object of the present invention is to provide a battery with a coulometric charge indicator device that can be used to indicate the capacity of the battery during discharge.
Another object of the present invention is to provide a battery with a coulometric charge indicator device that is cost effective to produce and reliable to use.
Another object is to provide a battery tester label for a battery containing a coulometric charge indicator device.