Electricity: battery or capacitor charging or discharging – Diverse charging or discharging rates for plural batteries
Reexamination Certificate
2000-02-28
2001-03-27
Tso, Edward H. (Department: 2838)
Electricity: battery or capacitor charging or discharging
Diverse charging or discharging rates for plural batteries
Reexamination Certificate
active
06208116
ABSTRACT:
The present invention is directed to a method for charging batteries, particularly in cordless communication devices.
In many types of electrical and electronic devices that are to be operated at least temporarily without a direct connection to the power network, particularly in mobile or cordless telephones, rechargeable batteries are mainly provided. These batteries are charged either in the fixed part of the respective device or in separate charging stations for re-use during mobile operation. A charging current matched to the battery utilized is thereby generated via a charging energy source, usually by a charging device connected to the power network, and this charging current is forwarded to the battery. However, particular emphasis must thereby be placed thereon that an overcharging of the batteries not occur, this leading to power losses, particularly given more frequent charging, and potentially leading to destruction in the worst case.
In order to avoid the overcharging of the batteries by the charging device of a cordless communication device, German Letters Patent 42 36 811 has proposed that the charging voltage be measured at certain time intervals and continuing to charge the batteries or ending the charging dependent on the course of the voltage charging curve that indicates the charging condition when rising, the charged condition when constant and the overcharging condition given subsequent drop. In particular, NiMH batteries having a significantly higher capacity than NiCd batteries are thus extremely sensitive to constant overcharging.
The exact measurement of the charging voltage curve with the required precision and under changing operating conditions, however, is often difficult to determine. On the other hand, the knowledge of the capacities of the batteries and their technology is a precondition for the disturbance-free and long-term operation in other methods for charging the batteries, so that switched batteries having a capacity and technology different from the original capacity and technology is not possible. The correct display of the charging condition or, the capacity of the new batteries is also not possible with the prior methods.
German Letters Patent 43 16 471 discloses a method for determining the charge condition of a rechargeable battery, whereby, in a measuring mode, the counter reading of an electronic counting device can be modified corresponding to the charging and discharge current and, in addition, is modified dependent on the actually existing residual capacity of the battery, whereby the counting device is supplied, on the one hand, with signals corresponding to the capacity of the battery, which decreases with age, and, on the other hand, with signals corresponding to the charged condition of the battery. The measuring mode comprises one or more adjustment cycles as well as one or more working cycles, whereby the adjustment cycle contains a discharge of the rechargeable battery up to the final discharge voltage, a charging up to fully charged, and, subsequently, another discharging to the final discharge voltage of the battery for determining the remaining capacity, and whereby, following the end of an adjustment cycle, at least one working cycle follows that begins with a full charging of the battery and that is followed by a discharge down to the final discharge voltage upon determination of the respective charged condition. The adjustment and working cycles are monitored with the counting device by administration of qualitative and quantitative measuring and control data. In a preferred exemplary embodiment of the method, the measuring mode comprises one adjustment cycle and many working cycles with a sequence of capacities, whereby each capacity is compared to that of the preceding work cycle and the result of the comparison is stored, and whereby the charging of the rechargeable battery in the following working cycle is determined by the comparison result from the preceding working cycle.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a method with which, regardless of the technology of the batteries utilizes, a constant overcharging of the batteries is dependably avoided even given different capacity, particularly given a value deviating from the original capacity and, thus, a long service life of the batteries can be assured. Further, a correct capacity display should be capable of being additionally automatically realized in the operated device.
This object is inventively achieved in accordance with the present invention in a method in that an initial charging phase of the batteries following initial insertion into the device up to full charging is provided; in that the batteries are subsequently at least partly discharged and a value representing the previously drawn capacity is generated at every point in time; in that, at the beginning of a renewed charging phase, this generated value is compared to a stored base value that represents the duration of the initial charging phase; and in that subsequent charging phases follow the initial charging phase wherein the batteries are at least partially charged when the generated value is less than or equal to the base value or wherein the batteries are at least partially charged dependent on the generated value that, over and above this, is stored as new base value when the generated value is higher than the base value hitherto stored and the batteries have a fully charged condition at the beginning of the discharge phase leading to the generated value. As a result of this method, the charging phases following the initial charging phase can be automatically exactly matched to the technology and capacity of the batteries utilized without the user having to input any data whatsoever of the batteries or having to implement adaptions himself, and without an overcharging of the batteries occurring during daily operation of the device, for example, a mobile radio telephone or a similar communication means. A longer and disturbance-free operation is thus assured without the user having to monitor the charging himself. The charging of the batteries can then always ensue quickly with maximum current without having to fear an overcharging. The at least partial discharging of the batteries following the initial charging phase can already advantageously occur as a result of the intended use of the device.
In an embodiment, there is provided a method for charging batteries, particularly in cordless communication devices, said method comprising the steps of:
inserting at least one battery into a device for a first time; after said insertion, during an initial charging phase, fully charging said battery;
after said full charging, at least partially discharging said battery;
generating at each point in time a value representing a capacity drawn up to said partial discharging;
after said partial discharge, given a start of a renewed charging phase, comparing said generated value to a stored base value representing a duration of said initial charging phase; and
after said comparison, during subsequent charging phases following said initial charging phase, at least partially charging said battery when said generated value is one of less than or equal to said base value and when said generated value that, over and above this, is stored as a new base value when said generated value is higher than said base value hitherto stored and said batteries have a fully charged condition at a beginning of a discharge phase leading to said generated value.
In an embodiment, it is provided that the batteries are completely discharged after the initial charging phase and a value representing the drawn capacity is thereby generated; and in that subsequent charging phases follow thereupon, wherein the batteries are at least partially charged dependent on the generated value, which is also stored as new base value when the generated value deviates from the base value and the batteries have a fully charged condition at the beginning of the discharge phase leading to the generated value
Schiff & Hardin & Waite
Siemens Aktiengesellschaft
Tso Edward H.
LandOfFree
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