1. Field of the Invention
The present disclosure relates to a control technique, and particularly to a control method for a storage battery and a control apparatus using the control method.
2. Description of the Related Art
An electronic device, including a portable electronic device, can be conventionally driven by a battery. In such an electronic device, when the amount of remaining power in the battery pack runs out during operation, a program or data may be destroyed. In order to prevent such destruction, the amount of remaining power of the battery is displayed.
However, the life or a fault of a battery is sometimes not displayed. Accordingly, malfunction of a battery is detected, information on the malfunction is detected, and the malfunction of the battery is determined based on the information (refer to Japanese Unexamined Patent Application Publication No. 2005-321983, for example).
An example of information on malfunction of a battery is state of health (SOH). In such a situation, the inventors have recognized the following problem. The SOH is generally derived by charging and discharging a battery. Accordingly, for a battery used in a method in which SOH cannot be estimated or for a malfunctioning battery, SOH cannot be measured. However, notification of degrees of deterioration of such batteries is also desired.
The present disclosure has been made in view of such a situation, and a purpose thereof is to provide a technique for giving notice of a degree of deterioration of a storage battery.
To solve the problem above, a control apparatus according to one embodiment includes an acquisition unit that acquires state of health of a storage battery provided to supply electric power to a load, in which the state of health shows a smaller value as the storage battery deteriorates, and a notification unit that performs notification when state of health acquired by the acquisition unit is smaller than a first threshold value. When the acquisition unit has not acquired state of health for a predetermined period, the notification unit performs notification if the elapsed period from the manufacture of the storage battery is longer than a second threshold value.
Another embodiment is a control method. The method includes acquiring state of health of a storage battery provided to supply electric power to a load, in which the state of health shows a smaller value as the storage battery deteriorates, and performing notification when acquired state of health is smaller than a first threshold value. When state of health has not been acquired for a predetermined period in the acquiring, notification is performed in the performing notification if the elapsed period from the manufacture of the storage battery is longer than a second threshold value.
Optional combinations of the aforementioned constituting elements, and implementations in the form of methods, apparatuses, systems, recording media, and computer programs may also be practiced as additional modes.
Embodiments will now be described, by way of example only, with reference to the accompanying drawings which are meant to be exemplary, not limiting, and wherein like elements are numbered alike in several Figures, in which:
A general description will be given before the embodiment is specifically described. An embodiment relates to a power distribution system in which a solar battery is connected in parallel to a commercial power system, power is supplied from a commercial power supply, the solar battery, and a storage battery to a load, and the storage battery is charged. If the commercial power supply fails, power from the solar battery or the storage battery is supplied to a load. While power is supplied from the commercial power supply, the storage battery may be set to not discharge. Since the performance of such a storage battery will deteriorate, notification of the degree of deterioration or the life of a storage battery is desired in order to prevent the situation where the storage battery cannot be used when it needs to be used.
The degree of deterioration or the life of a storage battery is determined based on state of health (SOH). The SOH is measured at the time of charging or discharging. However, in order to handle the case where discharge control is provided in which SOH cannot be measured, a power distribution system according to the present embodiment issues a warning when SOH has not been updated for a predetermined period of time, based on the elapsed time after the manufacture of the storage battery.
Each of
The solar battery 10 is a power device that uses photovoltaic effect and converts optical energy directly into electric power. As the solar battery 10, a silicon solar battery, a solar battery made of materials including various compound semiconductors, or a dye-sensitized solar battery (an organic solar battery) may be used. The solar battery 10 outputs generated power. The storage battery 12 is charged with power generated from a renewable energy source, such as power generated by the solar battery 10, or with power supplied from the commercial power supply 22.
One end of the conversion apparatus 14 is connected to the solar battery 10. The path between the conversion apparatus 14 and the solar battery 10 branches at a point, and the branch path is connected to the storage battery 12. Namely, the solar battery 10 and the storage battery 12 are connected in parallel to one end of the conversion apparatus 14 via the branch point. The other end of the conversion apparatus 14 is connected to the commercial power supply 22. The operation of the conversion apparatus 14 will be described later. The management apparatus 16 outputs, to the conversion apparatus 14, an instruction for controlling the operation of the storage battery 12. The conversion apparatus 14 also continuously monitors voltage fluctuation on the path between the first SW 18 and the commercial power supply 22 to determine whether the commercial power supply 22 is failing or supplying power, based on detected voltage fluctuation.
The general load 26 is AC driven electrical equipment. The general load 26 is connected to a path that branches off from the path between the conversion apparatus 14 and the commercial power supply 22. Also, a distribution board, which is not shown in the figures, is connected to a point on the path between the conversion apparatus 14 and the commercial power supply 22, on the commercial power supply 22 side from a branch point at which the path branches off to the commercial power supply 22.
The first SW 18 and the second SW 20 are switches for changing a route according to an instruction from the management apparatus 16. An instruction for turning on or off the first SW 18 or for switching of the second SW 20 is issued by the conversion apparatus 14. Alternatively, such an instruction may be issued by the management apparatus 16. In the normal state, the first SW 18 is turned on, and the second SW 20 is connected to the Y terminal. Accordingly, the Y terminal of the second SW 20 is connected to the specific load 24. As with the general load 26, the specific load 24 is also AC driven electrical equipment.
With regard to charging in the normal state, the charging of the storage battery 12 is performed in the following way. When the electric power company adopts an electricity rate system based on time zones, an electricity rate in the nighttime is set lower than that in the daytime. For example, the daytime may be defined as the period from 7 a.m. to 11 p.m., and the nighttime may be defined as the period from 11 p.m. to 7 a.m. of the following day. In the nighttime, the storage battery 12 is charged with power supplied from the commercial power supply 22 via the first SW 18 and the conversion apparatus 14. In this case, the conversion apparatus 14 converts the AC power received from the commercial power supply 22 into direct-current (DC) power and outputs the DC power to the storage battery 12.
In the daytime, power generated by the solar battery 10 is output to the conversion apparatus 14. In this case, the conversion apparatus 14 converts the DC power received from the solar battery 10 into AC power and outputs the AC power to the first SW 18. Accordingly, the power from the solar battery 10 is also supplied to the specific load 24 and the general load 26. When the amount of power generated by the solar battery 10 is larger than the amount of power consumed by the specific load 24 and general load 26, the excess power is used to charge the storage battery 12.
At the time of discharging in the normal state, the storage battery 12 is used to contribute to so-called “peak cut” for lowering the maximum value of use of commercial power during the daytime in which electricity use is generally increased.
Thus, the specific load 24 can receive power supply from the solar battery 10, storage battery 12, and commercial power supply 22 in the normal state and from the solar battery 10 and storage battery 12 even in the power failure state. On the other hand, the general load 26 can receive power supply from the solar battery 10, storage battery 12, and commercial power supply 22 in the normal state but cannot receive any power supply in the power failure state.
In the normal state as shown in
The conversion unit 50 is connected to the solar battery 10 and the storage battery 12 shown in
Also, the conversion unit 50 receives AC power at the AC-side terminal 64, generates DC power from the AC power, and outputs the DC power via the DC-side terminal 62. The AC power received at the AC-side terminal 64 is provided from the commercial power supply 22 via the first SW 18 shown in
The detection unit 52 receives AC power from the first SW 18, or from the commercial power supply 22, and detects the frequency of the AC power. In the power failure state or the recovered state, since the detection unit 52 does not receive AC power from the commercial power supply 22, the detection unit 52 does not detect the frequency of AC power. When it has detected a frequency, the detection unit 52 outputs information on the detected frequency to the setting unit 54; when it has not detected a frequency, the detection unit 52 outputs information thereon to the setting unit 54.
The setting unit 54 receives, from the detection unit 52, information on a frequency or information on the fact that a frequency has not been detected. Upon reception of information on a frequency, the setting unit 54 sets a frequency according to the frequency in the information, which is namely the frequency of AC power from the commercial power supply 22. In this example, the setting unit 54 sets the same frequency as the frequency of AC power from the commercial power supply 22. Such operation corresponds to the system cooperative operation mentioned previously, and the setting unit 54 defines the operation as a system cooperative mode.
Upon reception of information on the fact that a frequency has not been detected, the setting unit 54 sets a frequency that is independent of the frequency of AC power from the commercial power supply 22 and that has been set in the system cooperative mode performed in the past. Such operation corresponds to the independent operation mentioned previously, and the setting unit 54 defines the operation as an independent mode. In this way, the setting unit 54 sets a frequency of AC power to be generated by the conversion unit 50.
The acquisition unit 68 acquires SOH of the storage battery 12 when a certain amount of power has been discharged from the storage battery 12. The SOH shows a smaller value as the storage battery 12 deteriorates. The SOH is derived as follows.
SOH=(full charge capacity at the time)/(initial full charge capacity) (1)
The full charge capacity at the time is derived as follows.
Full charge capacity at the time=(factor K)×(current integration value I during a predetermined period) (2)
In the following, a calculation method for Formula (2) will be described.
The factor K is set in advance by measurement or the like. More specifically, the factor K is determined based on a difference amount of state of charge (hereinafter, referred to as “SOC”) for a predetermined voltage change. For example, when the predetermined voltage change is defined as a change from a voltage V1 to a voltage V2 (V1>V2) and when V1 corresponds to a voltage when SOC is 75% and V2 corresponds to a voltage when SOC is 50%, the factor K can be determined as follows.
Factor K=100/(75−50)=4
In addition, when the integration value of current that has flowed during a predetermined period, in which the battery has discharged until the voltage has changed from V1 to V2 (V1>V2), is 10 Ah, the full charge capacity at the time will be as follows.
Full charge capacity at the time=4×10 Ah
Since a decreased current can flow as the battery deteriorates, the current integration value is also decreased.
The acquisition unit 68 outputs acquired SOH to the processing unit 56. As described above, unless the voltage changes from V1 to V2, or unless the SOC changes from 75% to 50%, the factor K in Formula (2) cannot be obtained in the present embodiment. Accordingly, unless a certain amount of power is discharged from the storage battery 12 in the normal state, the full charge capacity at the time cannot be obtained, and hence, the SOH cannot be estimated.
The processing unit 56 receives SOH from the acquisition unit 68. The processing unit 56 then compares the SOH with a first threshold value, which is stored in the storage unit 70 and defined based on SOH. For example, it is assumed here that two first threshold values of 63% and 60% are stored. When the SOH is smaller than the larger first threshold value of 63%, the processing unit 56 determines the display of a notice for battery change. Accordingly, the processing unit 56 outputs an instruction for displaying a battery change notice to the display unit 58. Further, when the SOH is even smaller than the smaller first threshold value of 60%, the processing unit 56 determines the display of a warning for battery life. Accordingly, the processing unit 56 outputs an instruction for displaying a battery life warning to the display unit 58.
The display unit 58 displays each of various screens according to the process in the processing unit 56. Each of
There will be described time courses of the display of a battery change notice and that of a battery life warning on the display unit 58. Each of
When the acquisition unit 68 has not acquired SOH for a predetermined period, or when discharge control in which SOH cannot be acquired has been provided or SOH has not been able to be acquired because of malfunction of the storage battery 12 for a predetermined period, the processing unit 56 acquires information on the time of manufacture (hereinafter, referred to as a “date of manufacture”) of the storage battery 12 from the storage unit 70 or the storage battery 12. For example, the predetermined period may be defined as one year. The storage unit 70 stores the date of manufacture of the storage battery 12.
The processing unit 56 compares the elapsed period from the date of manufacture with a second threshold value, which is stored in the storage unit 70 and defined based on an elapsed period from a date of manufacture. For example, it is assumed here that two second threshold values of 6.5 years and 7 years are stored. When the elapsed period from the date of manufacture is longer than or equal to the smaller second threshold value of 6.5 years, the processing unit 56 determines the display of a battery change notice. Accordingly, the processing unit 56 outputs an instruction for displaying a battery change notice to the display unit 58. Further, when the elapsed period from the date of manufacture is even longer than or equal to the larger second threshold value of 7 years, the processing unit 56 determines the display of a battery life warning. Accordingly, the processing unit 56 outputs an instruction for displaying a battery life warning to the display unit 58. Also, the acquisition unit 68 may acquire an elapsed period from the date of manufacture, and the processing unit 56 may constantly compare the acquired elapsed period from the date of manufacture with a second threshold value. In this case, the processing unit 56 validates the comparison results at the time when a period for which charging or discharging is not performed exceeds a predetermined period, and determines the display of a battery change notice when the elapsed time is longer than or equal to the second threshold value of 6.5 years.
In the above, notification of a battery life has been described. In the following, displaying performed when the remaining amount of the storage battery 12 is running out will be described. Each of
The configuration above may be implemented by a CPU or memory of any given computer, an LSI, or the like in terms of hardware, and by a memory-loaded program or the like in terms of software. In the present embodiment is shown a functional block configuration realized by cooperation thereof. Therefore, it would be understood by those skilled in the art that these functional blocks may be implemented in a variety of forms by hardware only or a combination of hardware and software.
There will now be described an operation performed by the power distribution system 100 having the configuration set forth above.
According to an embodiment, even if SOH cannot be acquired for a predetermined period, a notice is provided based on the elapsed period from the date of manufacture, so that the user can be notified of a degree of deterioration of a storage battery. Since the user can be notified of a degree of deterioration of a storage battery, the situation can be prevented in which the storage battery has reached the end of its life when it needs to be used in an emergency, such as in a power failure. Also, since a battery change notice and a battery life warning are switched to be displayed according to the degree of deterioration, the state of the storage battery can be clearly indicated. When a battery change notice is changed to a battery life warning, the frequency of notification is increased, so that the user can be clearly notified of the risk. In addition, since the notice is changed according to whether the determination is made based on the SOH or based on the elapse period, the user can be notified of the determination criteria.
The present invention has been described with reference to an embodiment. The embodiment is intended to be illustrative only, and it will be obvious to those skilled in the art that various modifications to a combination of constituting elements or processes could be developed and that such modifications also fall within the scope of the present invention.
In an embodiment, the solar battery 10 is provided to generate electric power. However, the application is not limited thereto and, for example, besides the solar battery 10, another apparatus for generating electric power from a renewable energy source may be provided. An example may be a wind power generator. This modification allows greater flexibility in the configuration of the power distribution system 100.
In an embodiment, notification is performed by displaying a notice on the display unit 58. However, the operation is not limited thereto, and a speaker may be provided so as to perform voice notification, for example. This modification allows greater flexibility in the design of a notification means.
The outline of one embodiment is as follows. A control apparatus according to one embodiment of the present invention includes an acquisition unit that acquires state of health of a storage battery provided to supply electric power to a load, in which the state of health shows a smaller value as the storage battery deteriorates, and a notification unit that performs notification when state of health acquired by the acquisition unit is smaller than a first threshold value. When the acquisition unit has not acquired state of health for a predetermined period, the notification unit performs notification if the elapsed period from the manufacture of the storage battery is longer than a second threshold value.
When state of health smaller than the first threshold value becomes even smaller, the notification unit may change the mode of notification.
The notification unit may increase the frequency of notification as the state of health becomes smaller.
When an elapsed period longer than the second threshold value becomes even longer, the notification unit may change the mode of notification.
The control apparatus may further include a processing unit that stops charging and discharging of the storage battery. The processing unit may stop charging and discharging of the storage battery when the notification unit has changed the mode of notification.
The notification unit may increase the frequency of notification as the elapsed period becomes longer.
The notification unit may change the mode of notification according to whether the state of health acquired by the acquisition unit is smaller than the first threshold value or the elapsed period from the manufacture of the storage battery is longer than the second threshold value.
The control apparatus may further include a processing unit that stops charging and discharging of the storage battery. The processing unit may stop charging and discharging of the storage battery when the notification unit has changed the mode of notification.
The acquisition unit may acquire state of health of a storage battery provided to supply electric power to a load in the case where a commercial power supply fails.
Another embodiment is a control method. The method includes acquiring state of health of a storage battery provided to supply electric power to a load, in which the state of health shows a smaller value as the storage battery deteriorates, and performing notification when acquired state of health is smaller than a first threshold value. When state of health has not been acquired for a predetermined period in the acquiring, notification is performed in the performing notification if the elapsed period from the manufacture of the storage battery is longer than a second threshold value.
While the foregoing has described what are considered to be the best mode and/or other examples, it is understood that various modifications may be made therein and that the subject matter disclosed herein may be implemented in various forms and examples, and that they may be applied in numerous applications, only some of which have been described herein. It is intended by the following claims to claim any and all modifications and variations that fall within the true scope of the present teachings.
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/JP2012/003605 | 5/31/2012 | WO | 00 | 2/17/2015 |