The present invention relates generally to battery charging apparatus and methods therefor, and, more particularly, to a battery charger having gripper arms for gripping surfaces of a battery pack to maintain the battery pack in position at a charging position, thereat to permit application of a charging current by charging circuitry of the battery charger to the battery cells of the battery pack.
Oftentimes, an electrical device is constructed to be of a design to permit powering thereof by one or more batteries. In some instances, the use of a battery to power the electrical device is necessary when the electrical device is not, or cannot be, positioned proximate to a permanent power supply. In other instances, a battery is used to power the electrical device to increase the portability of the device as no power cable is required to interconnect the electrical device to a permanent, power supply. Typically, the one or more batteries used to power the electrical device are carried directly with the electrical device.
However, because a battery stores only finite amounts of energy, operation of the electrical device is limited by the energy storage capacity of the battery. Powering of the electrical device by the battery discharges the battery, and, once the battery becomes discharged, replacement of the battery is required to permit continued operation of the electrical device. Increasing the size (and weight) of the battery, while increasing the energy storage capacity of the battery, reduces the portability of the electrical device when the battery is carried therewith. Accordingly, a compromise is made between increased battery energy storage capacity and reduced portability of the electrical device.
A portable or transportable radiotelephone is one such electrical device which is typically powered by a battery power supply. The battery power supply is typically carried directly with the radiotelephone, and is of a size and weight which does not unduly constrain the portability of the radiotelephone.
When the radiotelephone is operative to send or to receive a modulated signal, the radiotelephone typically dissipates power at a rate of up to three watts. Conventional battery power supplies constructed to power such radiotelephones are of energy storage capacities permitting power dissipation at such a rate (i.e., operation of the radiotelephone) for approximately a one hour time period. If the battery power supply operative to power the radiotelephone is not initially fully charged, the operational period during which the radiotelephone may be operated at such a power level is, of course, commensurately reduced.
Once the battery power supply has been discharged beneath a certain level, the battery powering the radiotelephone must be removed and replaced with a new battery power supply to permit continued operation of the radiotelephone.
Rechargeable batteries have been developed and are commercially available. Some of such commercially-available, rechargeable batteries are of constructions designed for use to power radiotelephones. The use of rechargeable batteries is advantageous as, after discharge of the batteries, the rechargeable batteries may be recharged, and then reused. Some constructions of rechargeable batteries may be recharged, and reused, up to, and even in excess of, five hundred times.
A rechargeable battery construction used to power a portable radiotelephone is typically comprised of several discrete battery cells, connected in a series (or other) connection, and housed within a common housing. The housing, together with the battery cells, is sometimes referred to as a battery pack. For purposes of simplicity, such a construction is most times referred to simply by the term "battery." The present disclosure utilizes such simplified terminology except when the more precise terminology is required.
The batteries may be constructed to be of various energy storage capacities. For instance, by appropriately increasing the number of battery cells disposed in a single battery pack comprising the battery, the energy storage capacity of the battery may be increased.
Rechargeable batteries of various energy storage capacities for powering a portable radiotelephone are commercially available. When selecting amongst these various batteries, a user makes the aforementioned compromise between increased battery energy storage capacity and reduced portability of the radiotelephone. That is to say, a user selecting a battery power supply of increased energy storage capacity does so at the expense of an increase in the size and weight of the battery power supply so selected. Conversely, a user selecting a battery power supply of reduced size and weight does so at the expense of a decrease in the energy storage capacity of the battery power supply so selected.
A battery used to power a portable radiotelephone (or other electronic device) is usually device-specific. That is, the battery is constructed to permit the battery terminals thereof to be connected readily to corresponding contacts of a radiotelephone of a particular construction (or of an other electronic device of a particular construction). The battery terminals are positioned to facilitate connection with the contacts of the radiotelephone (or other electronic device). Typically the housing of the battery also includes structure to affix the battery to the radiotelephone to permit carriage of the battery with the radiotelephone. Batteries constructed to power other electronic devices are oftentimes similarly constructed.
Battery charging apparatus is also commercially available to permit recharging of rechargeable batteries. A battery charger comprising such battery charging apparatus is typically comprised of support structure for supporting one or more batteries, and charging circuitry for supplying a charging current of desired characteristics which charges the rechargeable battery when suitably positioned upon the support structure to connect the batteries to the charging circuitry of the battery charging apparatus.
Most frequently, a battery charger is coupled to an external power supply (typically, a conventional, electrical outlet of a household power supply). The battery charging circuitry is operative to convert the electrical characteristics of the externally-supplied power of the external power supply into a charging current of desired characteristics to be applied to the battery. The energy of the charging current applied to the rechargeable battery is converted into chemical energy which is stored by the battery. Application of such charging current to the rechargeable battery over the elapsed period of time permits the rechargeable battery to become fully recharged. The time period required to charge fully the rechargeable battery is dependent upon the battery type and energy storage capacity, the extent to which the battery has been discharged, and the magnitude of the charging current applied to the battery.
Certain battery chargers are of constructions which supply a relatively small magnitude current (such as, for example, C/10 value wherein C is the 1-hour capacity of a battery) to the battery, and battery chargers of other constructions supply a significantly larger current (such as, for example, C value) to the battery. Application of the large magnitude current to the battery is referred to as fast charging of the battery. Application of a small magnitude current to the battery is referred to as trickle charging of the battery. Several battery chargers are of constructions which permit the application of either the large current (i.e., the fast charging current) or the relatively small current (i.e., the trickle charging current) to the battery to recharge the battery thereby.
With the continual reduction in the physical dimensions of many electronic devices, the convenience of use of such devices has increased. In the particular instance of portable radiotelephones, the continual reduction in the dimensions of the portable radiotelephones has permitted convenient carriage of such radiotelephones by a user.
However, and as noted hereinabove, all battery power supplies are of finite energy storage capacities; accordingly, operation of such radio telephones by a single battery power source, even one of an increased energy storage capacity, is limited. After an extended period of use (such period of operation dependent upon the energy storage capacity of the battery), the battery must be replaced with a fresh battery or the battery must be recharged. In order to recharge the battery, a battery charger is required to supply the rechargeable battery, once depleted of stored energy, with a charging current. For the same reasons for which a reduction in the physical dimensions of electronic devices are desirable, a reduction in the physical dimensions of a battery charger operative to recharge a rechargeable battery is also desirable.
The battery charger must also be capable of receiving a battery of any of various energy storage capacities and, hence, physical dimensions.
What is needed, therefore, is a battery charger construction of minimal dimensions permitting recharging of any of many differently-sized rechargeable batteries.