Electricity: measuring and testing – Electrolyte properties – Using a battery testing device
Reexamination Certificate
1999-02-02
2001-08-28
Riley, Shawn (Department: 2838)
Electricity: measuring and testing
Electrolyte properties
Using a battery testing device
C324S433000, C320S132000, C320S134000
Reexamination Certificate
active
06281683
ABSTRACT:
TECHNICAL FIELD
This invention relates to rechargeable storage batteries and, more particularly, to a rapid determination of the condition or charge parameters of a battery, such as potential maximum charge capacity of a battery and the present charge of the battery.
BACKGROUND OF THE INVENTION
Cellular telephones, pagers, hand held games, portable radios, tape recorders, compact disk players, “boom” boxes, two-way mobile radios, laptop and portable computers, portable power tools, golf carts, electric vehicles, and powered wheelchairs all have at least one thing in common: they all use batteries. When getting ready to leave the home or office with one of these devices the user will ask himself one or more of the following questions: When did I last charge the battery? How much have I used it since then? Is there enough charge in the battery to last through my meeting or flight or trip? What is the state of my backup battery? When did I last charge it?
These questions go unanswered as batteries do not provide an indication of their present capacity. Some devices attempt to estimate the remaining charge by measuring the current drawn from the battery and the time that it is drawn. However, this method does not account for the natural discharge of the battery or the fact that an older battery may not be able to charge to 100% of its rated capacity.
Therefore, there is a need for a user to be able to quickly determine the present and potential capacity of a battery so that the user can make a decision as to whether to recharge the battery, or to bring a spare battery, or to install another battery.
SUMMARY OF THE INVENTION
The present invention provides for rapid determination of the charge parameters of a battery, such as the present charge of the battery and the potential or maximum charge capacity of the battery. One or more discharge pulses and rest periods are applied to the battery. The battery voltage is measured to provide voltages during the rest periods, and/or voltages during is the discharge pulses. The voltage differences among two or more of these measured voltages are used, alone or with the open circuit battery voltage, as an input to a curve, or a look-up table, or to an equation or algorithm, to determine the maximum capacity or condition of the battery and the present charge in the battery. This information is then displayed to the user so that the user will know the maximum capacity and the present charge of the battery. The user can then make an informed decision as to whether the battery is adequate for the project that the user has in mind. The charge parameters may also be output to another process, such as a charging process, to control or alter that process.
There are several different embodiments of the invention. These embodiments involve applying one or more rest periods and discharge pulses to the battery, taking one or more voltage measurements during the rest periods and/or the discharge pulses, determining a difference voltage, and using the difference voltage, alone or with an open circuit voltage, to determine one or more of the charge parameters of the battery. For example, one embodiment is applying a first rest period to the battery, applying a discharge pulse to the battery, applying a second rest period to the battery, measuring a first open circuit voltage of the battery during the first rest period, measuring a second open circuit voltage of the battery during the second rest period, determining a difference voltage by subtracting the second open circuit voltage from the first open circuit voltage, using the difference voltage to determine a charge parameter of the battery, and outputting the charge parameter. Another embodiment is applying a first rest period to the battery, applying a discharge pulse to the battery, applying a second rest period to the battery, measuring a first open circuit voltage of the battery during the first rest period, measuring a second open circuit voltage of the battery during the second rest period, determining a difference voltage by subtracting the second open circuit voltage from the first open circuit voltage, using the first open circuit voltage and the difference voltage to determine a charge parameter of the battery, and outputting the charge parameter.
Another embodiment is applying a plurality of rest periods and a plurality of discharge pulses to the battery, measuring a first loaded circuit voltage of the battery at a first point during a selected one of the discharge pulses which is subsequent to the selected one of the rest periods, measuring a second loaded circuit voltage of the battery at a second point during the first selected one of the discharge pulses, determining a difference voltage by subtracting the second loaded circuit voltage from the first loaded circuit voltage, using the difference voltage to determine a charge parameter of the battery, and outputting the charge parameter. Still another embodiment is applying a plurality of rest periods and a plurality of discharge pulses to the battery, measuring an open circuit voltage during a selected one of the rest periods, measuring a first loaded circuit voltage of the battery at a first point during a selected one of the discharge pulses which is subsequent to the selected one of the rest periods, measuring a second loaded circuit voltage of the battery at a second point during the first selected one of the discharge pulses, determining a difference voltage by subtracting the second loaded circuit voltage from the first loaded circuit voltage, using the first open circuit voltage and the difference voltage to determine a charge parameter of the battery, and outputting the charge parameter.
Some other variations and embodiments are described below.
Other features, and advantages of the present invention will become apparent upon reading the following description of the preferred embodiment, when taken in conjunction with the drawings and the claims.
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patent: 5721688 (1998-02-01), Bramwell
patent: 5889385 (1999-03-01), Podrazhansky et al.
patent: 2769095 (1999-04-01), None
patent: WO 98/58270 (1998-12-01), None
patent: WO 99/17128 (1999-04-01), None
patent: PCT/US00/02489 (2000-07-01), None
Kusharskiy Yefim Y.
Podrazhansky Yury M.
Enrev Corporation
LLP Troutman Sanders
Riley Shawn
Toatley Gregory J.
Warner Charles L.
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