Electricity: battery or capacitor charging or discharging – Battery or cell discharging – With charging
Reexamination Certificate
2001-04-13
2003-12-16
Tibbits, Pia (Department: 2838)
Electricity: battery or capacitor charging or discharging
Battery or cell discharging
With charging
C324S426000
Reexamination Certificate
active
06664764
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a power supply apparatus, a charge control apparatus, a charge control method, a computer, and an electric automobile; more particularly the invention is directed to a power supply apparatus equipped with a rechargeable battery, a charge control apparatus for controlling the charging of the battery provided in the power supply apparatus, a charge control method, a computer to which the charge control method is applied, and an electric automobile equipped with the power supply apparatus and the charge control apparatus.
BACKGROUND OF THE INVENTION
It is well known that mobile computing has become evermore pervasive, and, as a result, portable personal computers (hereinafter referred to as portable PCs) now have various sizes and diverse functions. Examples of these pervasive portable PCs include notebook PCs, palmtop PCs, and PDAs (Personal Data Assistants).
A portable PC typically includes a battery in the main body thereof. Due to the presence of a stored battery, storage battery or battery component (hereinafter referred to a stored battery) with a portable PC, even in an environment in which no commercial power supply is available, for instance, in a mobile environment such as a train, the user can use and operate the portable PC. Typically, in conjunction with the stored battery, a secondary battery is usually also employed which can be used repeatedly by charging.
With regard to the secondary battery, which can be used in computers such as the portable PC, various household electric appliances, and electric automobiles, it is known that an intelligent version of the battery can also be used wherein the intelligent battery may typically have a built-in electric circuit. In accordance with such a battery, the remaining capacity of the battery can be informed (e.g. by display) to the outside or external portion of the battery with a relatively high degree of accuracy due to the built-in electric circuit of the battery. Accordingly, for instance, by using the intelligent battery as the secondary battery for a portable PC, the user can anticipate in advance of the actual exhaustion of the battery as to how much of the remaining capacity is left during the use of the portable PC in an environment that does not allow the use of a commercial power source, so as to avoid a sudden shutdown of the PC during the use.
On the other hand, when both the secondary battery, as mentioned above, and an AC adapter for converting power by a commercial power source to power suitable for the side to be supplied with power are concurrently connected, it is usually designed to carry out the charging so that the battery capacity of the secondary battery always maintains 100%. However, there can be a problem that the chemical reaction in the battery accelerates and the secondary battery deteriorates in a shorter period of time than normal when the battery capacity is reduced by self-discharge where the charge is always maintained at 100% by active recharging.
Further, if the secondary battery is removed from the side to be supplied with power and preserved for a long period, self-discharging can occur, and as a result, it may be preserved in a completely discharged state; in this situation, a problem may occur in which the chemical reaction in the battery accelerates causing the secondary battery to deteriorate in a shorter period of time.
That is, generally a secondary battery has a battery capacity range suitable for preservation according to the type or the like of the secondary battery, and preservation in the battery capacity range is recommended by each secondary battery maker, though the progress of deterioration is accelerated if the secondary battery is preserved with a battery capacity being outside the range.
One technique which attempts to overcome the above problem is described in Published Unexamined Patent Application No. 8-33220, which is incorporated herein by reference.
In accordance with that technique, once the type of a removably structured secondary battery is determined, the charging and discharging of the battery are controlled to provide a capacity suitable for preservation of the secondary battery thereby suppressing the overall deterioration of the secondary battery in the preservation.
However, the technique described in the above-mentioned Published Unexamined Patent Application No. 8-33220 is limited in that it requires a means for determining the type of the secondary battery, whereby this means likely pushes the overall cost of the resulting component upwards. This additional means and additional cost are unnecessary and undesired results in attempting to overcome problems in the field, such as that described above.
Further, in the technique described in the above Published Unexamined Patent Application No. 8-33220, if the mode automatically switches to a preservation mode, the period of idle state of the secondary battery is measured by a timer that is provided external to the secondary battery; the preservation mode is entered when the duration of idle state reaches a predetermined period. However, when this technique is applied to an apparatus such as a portable PC that selectively uses the power of either the commercial power source or the secondary battery, and, in addition, the above timer is included in the apparatus, then the timer is reset if the AC adapter provided to supply commercial power to the apparatus is pulled out, so the mode cannot switch to the preservation mode with accurate timing. This result is also undesired to overcome the problems in the field.
SUMMARY OF THE INVENTION
The present invention is directed to a power supply apparatus in which deterioration of the power supply apparatus during its preservation can be suppressed at low cost while providing reliability. The present invention is also directed to providing a charge control apparatus and charge control method which can suppress the deterioration of the power supply apparatus during the preservation of the power supply apparatus at low cost while providing reliability. The present invention is further directed to providing a computer and an electric automobile to which the charge control method of the present invention can be applied.
The power supply apparatus according to the present invention is provided as an intelligent battery with a rechargeable battery and charge demanding means. The above rechargeable battery is inclusive, inter alia, of all secondary batteries such as lithium-ion battery, nickel-hydrogen battery, nickel-cadmium battery, and lithium-polymer battery. Further, the charge demanding means is inclusive of but not limited to an electric circuit such as a CPU (Central Processing Unit).
It In one aspect of the present invention for a power supply apparatus, a charge demand is output when the remaining capacity of the battery is detected, by the charge demanding means, and the remaining capacity becomes lower than a predetermined preservation capacity value or range which is suitable for preserving the battery.
The remaining battery capacity may be detected, for instance, by previously determining and storing the full-charge capacity, and then subtracting the discharge amount since the time of full-charge from the full-charge capacity value. Further, in relation to the remaining battery capacity, the voltage value of the battery which often increases or decreases depending on the remaining capacity, may be utilized.
Further, in an aspect of the present invention, the power supply apparatus is not connected to a load to,be supplied with power from the battery (i.e., the invention is of the form in which power is not supplied to the load though the apparatus is connected to the load, etc.). Furthermore, the preservation capacity is defined to include a single capacity value, as well as a capacity range having an upper limit capacity value and a lower limit capacity value. A charge demand is output when the remaining battery capacity becomes lower than the lower limit capacity value of the preservation capacity ran
Schelkopf J. Bruce
Tibbits Pia
LandOfFree
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