Electricity: battery or capacitor charging or discharging – Battery or cell discharging – With charging
Reexamination Certificate
2002-05-29
2004-01-27
Tso, Edward H (Department: 2838)
Electricity: battery or capacitor charging or discharging
Battery or cell discharging
With charging
Reexamination Certificate
active
06683440
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a detecting method for detecting internal information of a rechargeable battery to be inspected (this rechargeable battery will be hereinafter referred to as “inspective rechargeable battery”) and a detecting apparatus for detecting internal information of an inspective rechargeable battery. The present invention also relates to an apparatus in which said detecting method is applied and an apparatus including said detecting apparatus. The present invention includes a storage medium in which a software of said detecting method is stored.
The internal information to be detected in the present invention includes the presence or absence of short circuit, electricity storable capacity, remaining capacity (=presently stored electricity quantity=dischargeable capacity), usable capacity (=presently residual electricity quantity which is still able to operate an instrument), internal resistance, and the like, of an inspective rechargeable battery.
2. Related Background Art
In recent years, along with development of semiconductor elements and development of miniature, light-weight and high performance rechargeable batteries, mobile instruments such as portable personal computers, video cameras, digital cameras, cellular phones, and personal digital assistants including palmtop PCs have been rapidly progressed.
Separately, in recent years, the global warming of the earth because of the so-called greenhouse effect to an increase in the content of CO
2
gas in the air has been predicted. For instance, in thermal electric power plants, thermal energy obtained by burning a fossil fuel is converted into electric energy, and along with burning of such fossil fuel, a large amount of CO
2
gas is exhausted in the air. Accordingly, in order to suppress this situation, there is a tendency of prohibiting to newly establish a thermal electric power plant. Under these circumstances, so-called load leveling practice has been proposed in order to effectively utilize electric powers generated by power generators in thermal electric power plants or the like, wherein using a load conditioner having a rechargeable battery installed therein, a surplus power unused in the night is stored in rechargeable batteries installed at general houses and the power thus stored is used in the daytime when the demand for power is increased, whereby the power consumption is leveled.
Separately, in recent years, electric vehicles comprising a rechargeable battery and which do not exhaust any polluting substances have been proposed. Besides hybrid powered automobiles in which a combination of a rechargeable battery and an internal combustion engine or a fuel cell is used and the fuel efficiency is heightened while restraining exhaustion of polluting substances have been also proposed. As the rechargeable battery used in these electric vehicles and hybrid powered automobiles, a high performance rechargeable battery having a high energy density is expected to be developed.
Such rechargeable battery presently used in the mobile instrument, the load conditioner used for practicing the load leveling, the electric vehicle and the hybrid powered automobile includes typically rechargeable lithium batteries (lithium ion rechargeable batteries) in which reduction-oxidation reaction of lithium is used.
Incidentally, in the mobile instrument, the load conditioner in the load leveling, the electric vehicle and the hybrid powered automobile in which such rechargeable battery as above mentioned is used, it is possible to extend the operation time to the maximum by properly controlling the power outputted from the rechargeable battery depending on internal information of the battery on the side of the apparatus in which the battery is accommodated, or it is possible to avoid occurrence of sudden stall of the operation by previously knowing the time necessary to exchange the battery by way of acquisition of information of the lifetime of the battery in advance.
Particularly, in order to prevent the operation of the mobile instrument, the load conditioner, the electric vehicle or the hybrid powered automobile from being suddenly stopped, it is very important to be able to precisely detecting internal information of the rechargeable battery used therein, represented by electricity storable capacity, remaining capacity (=presently stored electricity quantity=dischargeable capacity), usable capacity (=presently residual electricity quantity which is still able to operate an instrument), and internal resistance of the battery.
In order to detect the remaining capacity of a rechargeable battery, there is known a method wherein the voltage of the battery is measured and based on the measured battery voltage, the usable capacity is estimated.
The term “remaining capacity” of the rechargeable battery means a presently stored electricity quantity of the battery which can be discharged. The term “usable capacity” means a presently available electricity quantity of the rechargeable battery with which an instrument (or an apparatus) having said rechargeable battery can be still operated. The usable capacity is included in the term remaining capacity.
Aforesaid method is applicable in the case of a lithium ion rechargeable battery whose anode material comprising a non-graphitizing carbon material which is distinguished from a graphite, where because the battery voltage is gradually decreased in proportion to the quantity of the electricity to be discharged, and therefore, the usable capacity of the rechargeable battery can be estimated by measuring the battery voltage. However, it is difficult to precisely detect the remaining capacity of the rechargeable battery by using this method because the battery voltage differs depending on an electric current flown even when the remaining capacity is identical. Besides, in the case where the performance of the rechargeable battery has been deteriorated to close its lifetime, it is extremely difficult to precisely detect the remaining capacity.
Separately, in the case of a lithium ion rechargeable battery whose anode material comprising a graphite series carbonous material, because the battery voltage with respect to the quantity of the electricity to be discharged is flat, it is difficult to estimate the remaining capacity from the battery voltage in accordance with aforesaid method.
There is also known a method in order to detect the remaining capacity of a rechargeable battery, wherein an accumulation discharged-electricity quantity is memorized and the accumulation discharged-electricity quantity is subtracted from a charged-electricity quantity to obtain a remaining capacity thereof. However, this method has such disadvantages as will be described in the following. That is, the current value and the discharge time are necessary to be always memorized. Besides, in the case where the discharge depth of the rechargeable battery is unknown with respect to the discharge depth and additional charging is performed for this rechargeable battery, although the charged-electricity quantity at that time can be detected, the remaining capacity of the rechargeable battery after the rechargeable battery is subjected to charging cannot be precisely detected because the remaining capacity of the rechargeable battery before the additional charging is unknown. When aforesaid method is adopted in this case, because the method is of a way to calculate a remaining capacity by subtracting the total discharged-electricity quantity from the accumulation charged-electricity quantity prior to the discharging, a large error is likely to occur in the measurement.
Therefore, the method is difficult to cope with a rechargeable battery whose performance has been deteriorated to close its lifetime, where it is difficult to precisely detect the remaining capacity.
Now, Japanese Laid-open Patent Publication No. Hei.4(1992)-2066 (hereinafter referred to as document 1) discloses a method for distinguishing the capaci
Degura Yasusaburo
Kawakami Soichiro
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Tso Edward H
LandOfFree
DETECTING METHOD FOR DETECTING INTERNAL INFORMATION OF A... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with DETECTING METHOD FOR DETECTING INTERNAL INFORMATION OF A..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and DETECTING METHOD FOR DETECTING INTERNAL INFORMATION OF A... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3242267