Computer program for power supply, power supply system, and power supply method

Abstract

To provide a computer program for a power supply, a power supply system, and a power supply method capable of suppressing deterioration of a storage device.SOLUTION: A computer program for a power supply is programmed to make a computer execute: state acquisition processing for acquiring a capacity maintenance rate SH1 of a storage device 5 for a vehicle; range setting processing for setting an SOC range ΔSOC such that the SOC range ΔSOC which can be charged for the storage device 5 is expanded when the capacity maintenance rate SH1 is equal to or less than a predetermined reference maintenance rate SSH1 based on the capacity maintenance rate SH1 acquired in the state acquisition processing; and power supply processing for controlling a charging / discharging device 20 that supplies power to the storage device 5 such that an SOC of the storage device 5 is within the SOC range ΔSOC set in the range setting processing.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a computer program for power supply, a power supply system, and a power supply method. [Background technology]

[0002] For example, Patent Document 1 discloses a management device that manages the exchange of power between a power grid and a secondary battery installed in a vehicle. This management device sets a first threshold value for the remaining performance of the secondary battery and a second threshold value that indicates a remaining performance higher than the first threshold value. When the remaining performance of the secondary battery is equal to or greater than the first threshold value but less than the second threshold value, the charging rate of the secondary battery is controlled within a narrower range than when the remaining performance is equal to or greater than the second threshold value.

[0003] For example, Patent Document 2 discloses a battery control system that includes a storage battery that is connected to a power grid and charges and discharges power, and a control device that controls the charging and discharging of the storage battery. This battery control system is configured to gradually shift to control that suppresses the deterioration of the storage battery as the storage battery's usage time increases and the storage battery's capacity maintenance rate decreases. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-195208 [Patent Document 2] Japanese Patent Publication No. 2020-162304 Summary of the Invention [Problem to be solved by the invention]

[0005] As described above, various techniques have been disclosed for suppressing the deterioration of power storage devices such as secondary batteries and storage batteries. The inventors of the present application wish to suppress the deterioration of power storage devices using a technique different from the techniques disclosed in Patent Documents 1 and 2. [Means for solving the problem]

[0006] The computer program for power supply proposed here causes a computer to execute the following steps: a status acquisition process for acquiring a capacity maintenance rate of a vehicle power storage device; a range setting process for setting an SOC range so as to widen the SOC range within which the power storage device can be charged when the capacity maintenance rate acquired in the status acquisition process is equal to or lower than a predetermined reference maintenance rate; and a power supply process for controlling a charging / discharging device that supplies power to the power storage device so that the SOC of the power storage device falls within the SOC range set in the range setting process.

[0007] The power supply method proposed here includes a status acquisition step of acquiring a capacity maintenance rate of a vehicle power storage device; a range setting step of setting an SOC range based on the capacity maintenance rate acquired in the status acquisition step when the capacity maintenance rate is equal to or lower than a predetermined reference maintenance rate, so as to widen the SOC range within which the power storage device can be charged; and a power supply step of controlling a charging / discharging device that supplies power to the power storage device so that the SOC of the power storage device falls within the SOC range set in the range setting step.

[0008] According to the proposed computer program for power supply and power supply method, when the capacity maintenance rate of a power storage device is higher than a reference maintenance rate, the SOC range is narrowed to suppress deterioration of the power storage device with a high capacity maintenance rate. Also, when the capacity maintenance rate of the power storage device is equal to or lower than the reference maintenance rate, the SOC range is widened to suppress deterioration of the power storage device with a low capacity maintenance rate. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a conceptual diagram illustrating a power supply system according to an embodiment. [Figure 2] 1 is a block diagram showing a power supply system according to an embodiment; [Figure 3] 4 is a flowchart showing a procedure for supplying power to a power storage device. [Figure 4] FIG. 1 is a graph showing the relationship between the capacity retention rate and the SOC range. [Figure 5] FIG. 1 is a graph showing the relationship between the capacity retention rate and the SOC range. [Figure 6] FIG. 1 is a graph showing the relationship between the capacity retention rate and the SOC range. [Figure 7] FIG. 10 is a diagram showing the relationship between elapsed time and capacity maintenance rate in the high SOC range, the medium SOC range, and the low SOC range. [Figure 8] FIG. 10 is a diagram showing the relationship between the elapsed time and the rate of increase in resistance in the high SOC range, the medium SOC range, and the low SOC range. [Figure 9] 10 is a flowchart showing an example of a procedure for determining an upper limit SOC and a lower limit SOC of an SOC range. [Figure 10] FIG. 10 is a diagram showing the relationship between outside air temperature and SOC range. [Figure 11] FIG. 10 is a diagram showing the relationship between the predicted mileage and the SOC range. [Figure 12] FIG. 10 is a diagram showing the relationship between the capacity maintenance rate and the SOC range in a modified example. [Figure 13] FIG. 10 is a diagram showing the relationship between the capacity maintenance rate and the SOC range in a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the power supply system disclosed herein will be described below with reference to the drawings. The embodiment described herein is, of course, not intended to limit the present invention. The present invention is not limited to the embodiment described herein unless otherwise specified. Furthermore, members and parts that perform the same function will be appropriately designated by the same reference numerals, and duplicate descriptions will be omitted where appropriate.

[0011] Fig. 1 is a conceptual diagram showing a power supply system 10 according to this embodiment. As shown in Fig. 1, the power supply system 10 according to this embodiment is a system that supplies power to a power storage device 5. The power supply system 10 is a system that manages charging of the power storage device 5. However, the power supply system 10 may also manage discharging of the power storage device 5.

[0012] The power storage device 5 is capable of being charged and discharged. The type of the power storage device 5 is not particularly limited. For example, a secondary battery that can be repeatedly charged and discharged by the movement of charge carriers between a pair of electrodes (for example, a positive electrode and a negative electrode) via an electrolyte can be used as the power storage device 5. For example, a lithium ion secondary battery or a nickel-metal hydride battery can be used as the power storage device 5.

[0013] The power storage device 5 is for use in a vehicle, for example. In this embodiment, the power storage device 5 is mounted on an electric vehicle 6. The electric vehicle 6 includes vehicles that use electric power as an energy source, such as electric automobiles, hybrid vehicles, and plug-in hybrid vehicles. The electric vehicle 6 may be a four-wheeled vehicle or a two-wheeled vehicle. The electric vehicle 6 may also be a bicycle.

[0014] In this embodiment, as shown in FIG. 1, a power supply system 10 includes a power source 15, a charging / discharging device 20, and a control device 30.

[0015] The power source 15 supplies power to the vehicle power storage device 5. There is no particular limitation on the number of power sources 15, and there may be one or more. There is also no particular limitation on the specific type of power source 15. The power source 15 refers to, for example, various types of power generation facilities. The types of power generated by the power generation facilities include natural gas, coal, oil, nuclear power, hydroelectric power, and renewable energy other than hydroelectric power. Examples of renewable energy include solar power, biomass, wind power, and geothermal power. The owner (or owner organization) of the power source 15 may be a company such as an electric power company, or may be a household. In FIG. 1, a solar power generation facility is illustrated as the power source 15. The power source 15 includes solar power generation facilities owned by a company or a household.

[0016] The charging / discharging device 20 is a device that charges or discharges the power storage device 5 of the electric vehicle 6. In this example, the charging / discharging device 20 is connected to a power source 15. The charging / discharging device 20 supplies power from the power source 15 to the power storage device 5, or receives power from the power storage device 5. The number of charging / discharging devices 20 is not particularly limited and may be one or more. The charging / discharging device 20 is installed in, for example, a charging / discharging spot 21. The charging / discharging spot 21 may be, for example, a parking lot in which the charging / discharging device 20 is installed. Parking lots for the charging / discharging spots 21 include parking lots of stores that sell products, parking lots of stores that provide services such as beauty salons, parking lots of commercial facilities, and parking lots of residential buildings. The electric vehicle 6 equipped with the power storage device 5 is parked in the parking lot of the charging / discharging spot 21 and connected to the charging / discharging device 20. With charging / discharging device 20 connected to electric vehicle 6, power is supplied from charging / discharging device 20 to power storage device 5, thereby charging the power storage device 5, or power is supplied from power storage device 5 to charging / discharging device 20, thereby discharging the power storage device 5. Although not shown in the figures, charging / discharging device 20 may be provided with a power storage device for charging / discharging device 20 for temporarily storing the power supplied from power source 15.

[0017] The control device 30 is a device that performs control related to charging or discharging of the power storage device 5 of the electric vehicle 6. The control device 30 mainly performs control to supply power supplied from the power source 15 from the charging / discharging device 20 to the power storage device 5. The configuration of the control device 30 is not particularly limited. Here, the control device 30 is, for example, a microcomputer. The control device 30 includes, for example, an input / output interface, a CPU, a ROM, and a RAM. The control device 30 may be realized by a single computer or may be realized by multiple computers working together.

[0018] The control device 30 is connected to the charging / discharging device 20 and the electric vehicle 6 so as to be able to communicate with them. In this embodiment, as shown in FIG. 1 , the control device 30 is electrically connected to the charging / discharging device 20 and the electric vehicle 6 via the Internet 2. Here, the electric vehicle 6 and the power storage device 5 are connected so as to be able to communicate with each other, and the control device 30 is connected so as to be able to communicate with the power storage device 5 via the electric vehicle 6. However, the control device 30 may also be directly connected so as to be able to communicate with the power storage device 5. The control device 30 controls the charging / discharging device 20 to charge / discharge the power storage device 5. The control device 30 also controls the electric vehicle 6 and the power storage device 5, and is able to acquire information relating to the electric vehicle 6 and the power storage device 5 from the electric vehicle 6 and the power storage device 5.

[0019] In this embodiment, the power supply system 10 may be realized by, for example, a client-server system or by so-called cloud computing. As shown in Fig. 1, the control device 30 may be a server installed on a cloud and connected via the Internet 2. However, the control device 30 may also be incorporated into the charging / discharging device 20.

[0020] Incidentally, a vehicle power storage device 5 deteriorates due to repeated charging and discharging. It is preferable to suppress the deterioration of the power storage device 5 as much as possible, and suppressing the deterioration of the power storage device 5 allows the same power storage device 5 to be used for a long period of time. Therefore, in this embodiment, the power supply system 10 suppresses the deterioration of the power storage device 5.

[0021] In this embodiment, a capacity maintenance rate of the power storage device 5 is acquired, and an SOC range of the power storage device 5 is set according to the capacity maintenance rate. Here, the capacity maintenance rate refers to the SOH (State Of Health) and is an index indicating the degradation state of the power storage device 5. The capacity maintenance rate is a ratio of the current full charge capacity to the initial full charge capacity of the power storage device 5, where the initial full charge capacity of the power storage device 5 is 100%. Here, the initial state of the power storage device 5 refers to, for example, a brand new power storage device 5, i.e., the power storage device 5 at the time of shipment. The initial state of the power storage device 5 may also refer to the time of final inspection before shipment. The full charge capacity refers to the amount of power charged to the power storage device 5 when the SOC of the power storage device 5 increases from 0% to 100%. The lower the capacity maintenance rate, the more deteriorated the power storage device 5 is presumed to be. The SOC range refers to the range of the amount of power that can be charged to the power storage device 5. The SOC range is set, for example, between 0% and 100%. The inventors of the present application have conducted various studies on means for suppressing degradation of the power storage device 5. As a result, the applicant of the present application found that it is possible to suppress the deterioration of the power storage device 5 by setting a narrow SOC range when the capacity maintenance rate of the power storage device 5 is high, i.e., when the power storage device 5 is not degraded, and by setting a wide SOC range when the capacity maintenance rate of the power storage device 5 is low, i.e., when the power storage device 5 is degraded. In this embodiment, "suppressing the deterioration of the power storage device 5" means suppressing the deterioration of the power storage device 5 to an extent that ensures the amount of power required by the user and does not reduce usability.

[0022] Fig. 2 is a block diagram showing a power supply system 10 according to this embodiment. As shown in Fig. 2, a control device 30 of the power supply system 10 includes a storage unit 31, a status acquisition unit 33, a range setting unit 35, and a power supply unit 37. Each of the units 31 to 37 of the control device 30 may be realized by one or more processors, or may be realized by being incorporated into a circuit.

[0023] Next, a procedure for supplying power to the power storage device 5 by the power supply system 10 according to this embodiment, that is, a procedure for charging the power storage device 5, will be described with reference to the flowchart of FIG.

[0024] First, in step S101 of FIG. 3 , a status acquisition process is executed. In the status acquisition process, a capacity maintenance rate SH1 of the vehicle power storage device 5 is acquired. Here, the status acquisition process is embodied by the status acquisition unit 33 of FIG. 2 . The status acquisition unit 33 acquires the current capacity maintenance rate SH1 of the power storage device 5. In the present embodiment, as described above, the electric vehicle 6 and the power storage device 5 are connected to be able to communicate with each other. Although not shown in the drawings, the electric vehicle 6 is provided with a means for periodically acquiring the capacity maintenance rate SH1 of the power storage device 5, and the capacity maintenance rate SH1 of the power storage device 5 is periodically stored in a memory unit (not shown) of the electric vehicle 6. The status acquisition unit 33 acquires the capacity maintenance rate SH1 of the power storage device 5 from the electric vehicle 6. However, the capacity maintenance rate SH1 of the power storage device 5 may not be stored in the electric vehicle 6, and the status acquisition unit 33 may acquire the capacity maintenance rate SH1 of the power storage device 5 detected by the electric vehicle 6. Furthermore, the status acquisition unit 33 may directly acquire the capacity maintenance ratio SH1 from the power storage device 5. The status acquisition unit 33 may be configured to detect, for example, the capacity maintenance ratio SH1 of the power storage device 5. The current capacity maintenance ratio SH1 of the power storage device 5 acquired by the status acquisition unit 33 is stored in the storage unit 31 of FIG. 2.

[0025] The status acquisition unit 33 may acquire information other than the capacity maintenance rate SH1 of the power storage device 5, such as information about the electric vehicle 6 (for example, the driving history, model year, and type of the electric vehicle 6), or may acquire information about charging and discharging the power storage device 5. Here, the driving history refers to the total driving distance of the electric vehicle 6, the driving distance for each predetermined period (for example, each day), etc. The status acquisition unit 33 can also acquire the current battery capacity of the power storage device 5, the outside air temperature of the electric vehicle 6, etc.

[0026] Next, in step S103 of FIG. 3, a range setting process is executed. In the range setting process, an SOC range ΔSOC of the power storage device 5 is set based on the capacity maintenance rate SH1 of the power storage device 5. In this embodiment, the range setting process is embodied by the range setting unit 35 of FIG. 2. The range setting unit 35 sets the range (in other words, the width) of the SOC range ΔSOC based on the capacity maintenance rate SH1 acquired by the status acquisition unit 33. FIGS. 4, 5, and 6 are diagrams showing the relationship between the capacity maintenance rate SH1 and the SOC range ΔSOC. In FIGS. 4 to 6, the horizontal axis represents the capacity maintenance rate SH1, and the vertical axis represents the SOC range ΔSOC. On the horizontal axis, the capacity maintenance rate SH1 decreases as the arrow moves (to the right in this case). In this embodiment, as shown in FIG. 4, the SOC range ΔSOC has an upper limit SOC (Max1) and a lower limit SOC (Min1). The upper limit SOC (Max1) represents the upper limit of the SOC range ΔSOC. The lower limit SOC (Min1) indicates the lower limit of the SOC range ΔSOC. Therefore, the SOC range ΔSOC is the range between the upper limit SOC (Max1) and the lower limit SOC (Min1). The range setting unit 35 in FIG. 2 changes the upper limit SOC (Max1) or the lower limit SOC (Min1) based on the capacity maintenance rate SH1 to adjust the width (e.g., range) of the SOC range ΔSOC.

[0027] In this embodiment, the range setting unit 35 sets the SOC range ΔSOC so that the SOC range ΔSOC becomes wider (i.e., the range becomes larger) as the capacity maintenance ratio SH1 becomes lower. For example, as shown in Fig. 5, the range setting unit 35 sets the SOC range ΔSOC so that the upper limit SOC (Max1) becomes higher as the capacity maintenance ratio SH1 becomes lower. Furthermore, the range setting unit 35 sets the SOC range ΔSOC so that the lower limit SOC (Min1) becomes higher as the capacity maintenance ratio SH1 becomes lower.

[0028] For example, a reference maintenance rate SSH1 is pre-stored in the storage unit 31 of FIG. 2 . The reference maintenance rate SSH1 is a reference value for changing the range of the SOC range ΔSOC. The specific value of the reference maintenance rate SSH1 is set appropriately depending on the type of the power storage device 5, the initial full charge capacity, and the like. Here, when the capacity maintenance rate SH1 acquired by the state acquisition unit 33 is equal to or lower than the reference maintenance rate SSH1, the range setting unit 35 sets the SOC range ΔSOC so that the SOC range ΔSOC is wide. For example, as shown in FIG. 4 , when the capacity maintenance rate SH1 is equal to or lower than the reference maintenance rate SSH1 (here, the second reference maintenance rate SSH12), the range setting unit 35 may set the SOC range ΔSOC so that the upper limit SOC (Max1) of the SOC range ΔSOC is high. Furthermore, when the capacity maintenance rate SH1 is equal to or lower than the reference maintenance rate SSH1 (here, the first reference maintenance rate SSH11), the range setting unit 35 may set the SOC range ΔSOC so that the lower limit SOC (Min1) of the SOC range ΔSOC is low.

[0029] Note that there may be one or more reference maintenance rates SSH1. Furthermore, the reference maintenance rate SSH1 may be set separately for the upper limit SOC (Max1) and the lower limit SOC (Min1). The SOC range ΔSOC may be set so that the range becomes larger in stages according to the capacity maintenance rate SH1. For example, as shown in FIG. 4, the reference maintenance rate SSH1 has a first reference maintenance rate SSH11 and a second reference maintenance rate SSH12. Here, the second reference maintenance rate SSH12 is lower than the first reference maintenance rate SSH11. For example, the first reference maintenance rate SSH11 is 85%, and the second reference maintenance rate SSH12 is 70%.

[0030] In the example of FIG. 4, the range setting unit 35 of FIG. 2 sets an initial SOC range ΔSOC0 as the initial value of the SOC range ΔSOC. The initial SOC range ΔSOC0 is set for the SOC range ΔSOC of a brand new power storage device 5 (for example, a power storage device 5 with a capacity maintenance rate SH1 of 100%). For example, the initial SOC range ΔSOC0 is Δ60%, the upper limit SOC (Max1) is 80%, and the lower limit SOC (Min1) is 20%. When the capacity maintenance rate SH1 of the power storage device 5 becomes equal to or less than the first reference maintenance rate SSH11, the range setting unit 35 widens the SOC range ΔSOC from the initial SOC range ΔSOC0 to a first SOC range ΔSOC1. For example, the first SOC range ΔSOC1 is Δ80%, the upper limit SOC (Max1) is 80%, and the lower limit SOC (Min1) is 0%. When the capacity maintenance rate SH1 becomes equal to or less than the second reference maintenance rate SSH12, the range setting unit 35 widens the SOC range ΔSOC from the first SOC range ΔSOC1 to the second SOC range ΔSOC2. For example, the second SOC range ΔSOC2 is 100%, and the upper limit SOC (Max1) is 100% and the lower limit SOC (Min1) is 0%.

[0031] As described above, in this embodiment, when the capacity maintenance rate SH1 of the power storage device 5 decreases, the range setting unit 35 first lowers the lower limit SOC (Min1) of the SOC range ΔSOC to widen the SOC range ΔSOC. Then, when the capacity maintenance rate SH1 of the power storage device 5 decreases, the range setting unit 35 lowers the lower limit SOC (Min1) to a minimum value (e.g., 0%) and then increases the upper limit SOC (Max1) to widen the SOC range ΔSOC. More specifically, when the capacity maintenance rate SH1 of the power storage device 5 is the first reference maintenance rate SSH11, the range setting unit 35 lowers the lower limit SOC (Min1) to widen the SOC range ΔSOC from the initial SOC range ΔSOC0 to the first SOC range ΔSOC1. When the capacity maintenance rate SH1 is a second standard maintenance rate SSH12 that is lower than the first standard maintenance rate SSH11, the range setting unit 35 widens the SOC range ΔSOC from the first SOC range ΔSOC1 to the second SOC range ΔSOC2 by increasing the upper limit SOC (Max1) without changing the lower limit SOC (Min1).

[0032] When lowering the lower limit SOC(Min1), the range setting unit 35 may lower the lower limit SOC(Min1) all at once when the capacity maintenance rate SH1 becomes equal to the first reference maintenance rate SSH11, as shown in the example of FIG. 4 . Alternatively, when lowering the lower limit SOC(Min1), the range setting unit 35 may gradually lower the lower limit SOC(Min1) in accordance with the capacity maintenance rate SH1, as shown in FIGS. 5 and 6 . For example, as shown in the example of FIG. 5 , when the capacity maintenance rate SH1 is in a range greater than the first reference maintenance rate SSH11 (here, the range from the initial value (100%) to the first reference maintenance rate SSH11), the range setting unit 35 may gradually (e.g., continuously) lower the lower limit SOC(Min1) as the capacity maintenance rate SH1 decreases (i.e., as the capacity maintenance rate SH1 approaches the first reference maintenance rate SSH11). In this case, the lower limit SOC(Min1) may decrease at a constant rate, i.e., linearly at a constant slope, as the capacity maintenance rate SH1 decreases. Furthermore, as shown in FIG. 6, the lower limit SOC (Min1) may decrease at a variable rate as the capacity maintenance ratio SH1 decreases, that is, may decrease in a curved manner with a variable slope according to the capacity maintenance ratio SH1.

[0033] Similarly, when increasing the upper limit SOC(Max1), the range setting unit 35 may increase the upper limit SOC(Max1) all at once when the capacity maintenance rate SH1 becomes equal to the second reference maintenance rate SSH12, as shown in the example of FIG. 4. Alternatively, when increasing the upper limit SOC(Max1), the range setting unit 35 may gradually increase the upper limit SOC(Max1) in accordance with the capacity maintenance rate SH1, as shown in FIGS. 5 and 6. For example, as shown in the example of FIG. 5, the range setting unit 35 may gradually (e.g., continuously) increase the upper limit SOC(Max1) as the capacity maintenance rate SH1 decreases (i.e., as the capacity maintenance rate SH1 approaches the second reference maintenance rate SSH12) within the range where the capacity maintenance rate SH1 is between the first reference maintenance rate SSH11 and the second reference maintenance rate SSH12. In this case, the upper limit SOC(Max1) may increase at a constant rate, i.e., linearly at a constant slope, as the capacity maintenance rate SH1 decreases. 6, the upper limit SOC (Max1) may increase at a variable rate as the capacity maintenance ratio SH1 decreases, that is, may increase in a curved manner with a variable slope according to the capacity maintenance ratio SH1. Note that the specific procedure for calculating the upper limit SOC (Max1) and lower limit SOC (Min1) of the SOC range ΔSOC will be described later.

[0034] Next, in step S105 of FIG. 3, a power supply process is executed. The power supply process is a process of supplying power to the power storage device 5, i.e., a process of charging the power storage device 5. In this embodiment, the power supply process is embodied by the power supply unit 37 of FIG. 2. The power supply unit 37 controls the charging / discharging device 20 (see FIG. 1) that supplies power to the power storage device 5 so that the SOC of the power storage device 5 falls within the SOC range ΔSOC set in the range setting process. Here, the power supply unit 37 controls the charging / discharging device 20 to adjust the amount of power supplied to the power storage device 5 so that the SOC of the power storage device 5 does not exceed the upper limit SOC (Max1) of the SOC range ΔSOC. Note that in this embodiment, the power storage device 5 can be discharged. Therefore, the power supply unit 37 controls the charging / discharging device 20 to adjust the amount of discharge from the power storage device 5 so that the SOC of the power storage device 5 does not fall below the lower limit SOC (Min1) of the SOC range ΔSOC.

[0035] In this embodiment, for example, the power supply unit 37 determines the amount of power so that the SOC of the power storage device 5 falls within the SOC range ΔSOC. For example, this amount of power decreases as the SOC of the power storage device 5 approaches an upper limit SOC (Max1), and increases as the SOC approaches a lower limit SOC (Min1). The power supply unit 37 transmits the amount of power to be supplied to the power storage device 5 to the charging / discharging device 20. The charging / discharging device 20 obtains the amount of power transmitted from the power supply unit 37 from the power source 15 and transmits it to the power storage device 5. As a result, the power storage device 5 is supplied with power equal to the amount of power transmitted from the power supply unit 37. As a result, power is supplied to the power storage device 5 so that the SOC falls within the SOC range ΔSOC.

[0036] There may be multiple modes (e.g., control procedures) for supplying power to the power storage device 5. Examples of the modes include a manual mode and an automatic mode. The manual mode is a mode in which the user starts charging the power storage device 5 by operating an application (not shown) that operates the charging / discharging device 20. The application is pre-installed in a terminal such as a smartphone used by the user. The user operates the terminal to start charging / discharging the power storage device 5 through the application, and the power supply unit 37 in FIG. 2 controls charging / discharging the power storage device 5 so that the SOC of the power storage device 5 does not exceed an upper limit SOC (Max1) of the SOC range ΔSOC and does not fall below a lower limit SOC (Min1).

[0037] On the other hand, the automatic mode is a mode in which the control device 30 automatically starts charging and discharging the power storage device 5 without the user operating the above-mentioned application or the like. In the automatic mode, a charge and discharge plan is automatically created based on the frequency of use of the electric vehicle 6 by the user. This charge and discharge plan is created so that the SOC of the power storage device 5 does not become higher than the upper limit SOC (Max1) of the SOC range ΔSOC and does not become lower than the lower limit SOC (Min1). In the automatic mode, the power supply unit 37 controls the charging and discharging device 20 to charge and discharge the power storage device 5 in accordance with the charge and discharge plan created as described above.

[0038] As described above, in this embodiment, in the state acquisition process, the capacity maintenance rate SH1 of the vehicle power storage device 5 is acquired as in step S101 of FIG. 3. In the range setting process, as in step S103 of FIG. 3, based on the capacity maintenance rate SH1 acquired in the state acquisition process, as shown in FIG. 5, when the capacity maintenance rate SH1 is equal to or lower than a predetermined reference maintenance rate SSH1, an SOC range ΔSOC is set so that the SOC range ΔSOC within which the power storage device 5 can be charged is widened. In the power supply process, as in step S105 of FIG. 3, the charging / discharging device 20 (see FIG. 1) that supplies power to the power storage device 5 is controlled so that the SOC of the power storage device 5 falls within the SOC range ΔSOC set in the range setting process. As a result, when the capacity maintenance rate SH1 of the power storage device 5 is higher than the reference maintenance rate SSH1, the SOC range ΔSOC is narrowed, thereby making it possible to suppress deterioration of a power storage device 5 with a high capacity maintenance rate SH1 (for example, a brand new power storage device 5). Furthermore, when the capacity maintenance rate SH1 of the storage device 5 is equal to or lower than the reference maintenance rate SSH1, the SOC range ΔSOC is widened, thereby preventing further deterioration of the storage device 5 that has already deteriorated and has a low capacity maintenance rate SH1.

[0039] In the range setting process of this embodiment, as shown in Fig. 5, when the capacity maintenance rate SH1 is equal to or lower than the reference maintenance rate SSH1 (here, the second reference maintenance rate SSH12), the SOC range ΔSOC is set so that the upper limit SOC (Max1) of the SOC range ΔSOC is increased. In this way, by increasing the upper limit SOC (Max1), the power storage device 5 can be charged until the SOC of the power storage device 5 becomes high. Therefore, the amount of power that can be charged to the power storage device 5 can be increased.

[0040] 5, in the range setting process, the SOC range ΔSOC is set so that the lower limit SOC (Min1), which is the lower limit of the SOC range ΔSOC, is low when the capacity maintenance rate SH1 is equal to or lower than the reference maintenance rate SSH1 (here, the first reference maintenance rate SSH11). In this way, by lowering the lower limit SOC (Min1), it is possible to widen the range on the lower limit side of the SOC range ΔSOC in the power storage device 5. Therefore, it is possible to widen the SOC range ΔSOC.

[0041] In this embodiment, the reference maintenance rate SSH1 has a first reference maintenance rate SSH11 and a second reference maintenance rate SSH12 that is lower than the first reference maintenance rate SSH11. In the range setting process, when the capacity maintenance rate SH1 is equal to or lower than the first reference maintenance rate SSH11, the SOC range ΔSOC is set so that the lower limit SOC (Min1) of the SOC range ΔSOC is lowered. In addition, in the range setting process, when the capacity maintenance rate SH1 is equal to or lower than the second reference maintenance rate SSH12, the SOC range ΔSOC is set so that the upper limit SOC (Max1) of the SOC range ΔSOC is higher. In this way, in this embodiment, when the capacity maintenance rate SH1 is lower, the lower limit SOC (Min1) is first lowered to widen the SOC range ΔSOC, and then the upper limit SOC (Max1) is raised to further widen the SOC range ΔSOC.

[0042] Fig. 7 is a diagram showing the relationship between elapsed time and the capacity maintenance rate SH1 when the SOC range ΔSOC is in the high SOC range ΔSC3, the medium SOC range ΔSC2, and the low SOC range ΔSC1. Fig. 8 is a diagram showing the relationship between elapsed time and the resistance increase rate when the SOC range ΔSOC is in the high SOC range ΔSC3, the medium SOC range ΔSC2, and the low SOC range ΔSC1. Fig. 7 shows the change in the capacity maintenance rate SH1 over time when the SOC range ΔSOC of the power storage device 5 is in the high SOC range ΔSC3 (SOC range of 40% to 90%), the medium SOC range ΔSC2 (SOC range of 25% to 75%), and the low SOC range ΔSC1 (SOC range of 10% to 60%). Fig. 8 shows the change in the resistance increase rate of the power storage device 5 over time when the SOC range ΔSOC of the power storage device 5 is in the high SOC range ΔSC3, the medium SOC range ΔSC2, and the low SOC range ΔSC1. As shown in FIG. 7, by setting the SOC range ΔSOC to the low SOC range ΔSC1, the capacity maintenance ratio SH1 is less likely to decrease over time. On the other hand, by setting the SOC range ΔSOC to the high SOC range ΔSC3, the capacity maintenance ratio SH1 is more likely to decrease over time than in other ranges (the medium SOC range ΔSC2 and the low SOC range ΔSC1). As shown in FIG. 8, the rate of increase in resistance over time can be reduced in the following order: the medium SOC range ΔSC2, the low SOC range ΔSC1, and the high SOC range ΔSC3. That is, when the SOC range ΔSOC is in the medium SOC range ΔSC2, the rate of increase in resistance can be reduced most effectively. For these reasons, setting the SOC range ΔSOC to the low SOC range ΔSC1 makes it less likely for the capacity maintenance ratio SH1 to decrease and the rate of increase in resistance can be reduced compared to setting it to the high SOC range ΔSC3, thereby suppressing deterioration of the power storage device 5.

[0043] Therefore, as shown in Figure 5, when the capacity maintenance rate SH1 of the storage device 5 becomes low, the lower limit SOC (Min1) is first lowered and the SOC range ΔSOC is widened from the medium SOC range ΔSC2 to the low SOC range ΔSC1, thereby making the storage device 5 less susceptible to deterioration.

[0044] In the present embodiment, as shown in FIG. 5 , in the range setting process, the SOC range ΔSOC is set so that, in a range where the capacity maintenance rate SH1 is greater than the first reference maintenance rate SSH1 (here, the range between 100% and the first reference maintenance rate SSH1), the lower limit SOC (Min1) decreases as the capacity maintenance rate SH1 approaches the first reference maintenance rate SSH11. Furthermore, in the range setting process, the SOC range ΔSOC is set so that, in a range where the capacity maintenance rate SH1 is between the first reference maintenance rate SSH11 and the second reference maintenance rate SSH12, the upper limit SOC (Max1) increases as the capacity maintenance rate SH1 approaches the second reference maintenance rate SSH12. In this way, in the present embodiment, the SOC range ΔSOC can be gradually widened by gradually lowering the lower limit SOC (Min1). Furthermore, the SOC range ΔSOC can be gradually widened by gradually increasing the upper limit SOC (Max1). Therefore, the SOC range ΔSOC can be broadened in stages in accordance with the capacity maintenance ratio SH1, and therefore the width of the SOC range ΔSOC can be set appropriately in accordance with the capacity maintenance ratio SH1.

[0045] Next, an example of a procedure for determining the upper limit SOC (Max1) and the lower limit SOC (Min1) of the SOC range ΔSOC will be described with reference to the flowchart of FIG.

[0046] Here, the storage unit 31 in FIG. 2 stores vehicle information related to the power storage device 5 and the electric vehicle 6 in advance. This vehicle information is, for example, information acquired from the power storage device 5 or the electric vehicle 6 by the state acquisition unit 33 in FIG. 2. Examples of the vehicle information include an expected mileage D1 of the electric vehicle 6 for a predetermined period (e.g., one day), an outside temperature T1 of the electric vehicle 6, a required amount of energy E1, a current capacity maintenance rate SH1 of the power storage device 5, a current battery capacity C1 of the power storage device 5, an SOC range ΔSOC, an initial SOC range ΔSOC0, and an SOC reference value SOC1. The outside temperature T1 refers to the temperature around the electric vehicle 6, for example, the environmental temperature when the electric vehicle 6 is stopped. The outside temperature T1 refers to, for example, the average temperature for that day. The required amount of energy E1 refers to the battery capacity of the power storage device 5 required for the electric vehicle 6 to travel the expected mileage D1 for a predetermined period (e.g., one day).

[0047] As described above, the SOC range ΔSOC is predetermined based on the current capacity maintenance rate SH1 of the power storage device 5. However, the upper limit SOC (Max1) and lower limit SOC (Min1) of the SOC range ΔSOC are not determined. The initial SOC range ΔSOC0 is the range of the SOC range ΔSOC when the capacity maintenance rate SH1 is 100%, and is predetermined. The upper limit SOC (Max1) and lower limit SOC (Min1) of the initial SOC range ΔSOC0 are predetermined. The SOC reference value SOC1 is a reference value used when determining the upper limit SOC (Max1) and lower limit SOC (Min1) of the SOC range ΔSOC. The SOC range ΔSOC may be calculated based on the initial SOC range ΔSOC0 and the capacity maintenance rate SH1. The SOC range ΔSOC can be calculated, for example, using the formula ΔSOC = ΔSOC0 × (1 / SH1).

[0048] The SOC reference value SOC1 is set, for example, for the initial SOC range ΔSOC0. Here, the SOC reference value SOC1 is the intermediate value of the initial SOC range ΔSOC0, that is, half the difference between the upper limit SOC (Max1) and the lower limit SOC (Min1) of the initial SOC range ΔSOC0. The SOC reference value SOC1 is, for example, a value between 40% and 60%.

[0049] In this embodiment, the control for determining the upper limit SOC (Max1) and lower limit SOC (Min1) of the SOC range ΔSOC is performed by the range setting unit 35 shown in FIG. 2. First, in step S201 of FIG. 9, the range setting unit 35 determines whether the SOC range ΔSOC is equal to or greater than a required ratio R1, which is the ratio of the required energy E1 to the current battery capacity C1. Here, the required ratio R1 is the required energy E1 divided by the battery capacity C1 and can be expressed as E1 / C1. If the SOC range ΔSOC is less than the required ratio R1, the process proceeds to step S203 of FIG. 9. If the SOC range ΔSOC is less than the required ratio R1, it is likely that the required energy E1 will not be charged to the power storage device 5 even if the maximum amount of energy within the SOC range ΔSOC is charged. In this case, the range setting unit 35 changes the specific value of the SOC range ΔSOC to the required ratio R1. After changing the value of the SOC range ΔSOC to the required ratio R1 in this way, the process proceeds to step S205 in FIG.

[0050] On the other hand, if it is determined in step S201 that the SOC range ΔSOC is equal to or greater than the required rate R1, the process proceeds to step S205 without changing the specific value of the SOC range ΔSOC. In step S205, the range setting unit 35 calculates a difference B1. The difference B1 is the difference between the set SOC range ΔSOC and the initial SOC range ΔSOC0. The difference B1 is calculated, for example, using the formula B1 = ΔSOC - ΔSOC0. In this embodiment, as described above, as shown in FIG. 5, the range of the SOC range ΔSOC widens as the capacity maintenance rate SH1 decreases. On the other hand, the initial SOC range ΔSOC0 is a fixed value. Therefore, the difference B1 indicates the degree of deterioration of the power storage device 5 as the capacity maintenance rate SH1 decreases. The larger the difference B1, the greater the degree of deterioration of the power storage device 5. The calculated difference B1 is stored in the storage unit 31 of FIG. 2.

[0051] Next, in step S207 of FIG. 9, the range setting unit 35 determines the difference B1. Here, it determines whether the difference B1 is equal to or less than the SOC reference value SOC1 minus half of the initial SOC range ΔSOC0, that is, whether the difference B1 is equal to or less than "SOC1-ΔSOC0 / 2." Here, "SOC1-ΔSOC0 / 2" is a comparison value used to prevent the lower limit SOC (Min1) from being set to less than 0%. If it is determined in step S207 that the difference B1 is equal to or less than "SOC1-ΔSOC0 / 2," the process proceeds to step S209 of FIG. 9.

[0052] In step S209, the range setting unit 35 determines the upper limit SOC (Max1) and lower limit SOC (Min1) of the SOC range ΔSOC so that the lower limit SOC (Min1) is lower. In step S209, the range setting unit 35 fixes the value of the upper limit SOC (Max1) and sets the value of the lower limit SOC (Min1) to be lower. That is, in step S209, the upper limit SOC (Max1) and lower limit SOC (Min1) are set when the capacity maintenance rate SH1 in FIG. 5 is between 100% and the first reference maintenance rate SSH11. Here, the range setting unit 35 sets the upper limit SOC (Max1) to a value obtained by adding half the initial SOC range ΔSOC0 to the SOC reference value SOC1. That is, the upper limit SOC (Max1) is a fixed value calculated using the formula Max1 = SOC1 + ΔSOC0 / 2. Meanwhile, the range setting unit 35 sets the lower limit SOC (Min1) to a value obtained by subtracting half the initial SOC range ΔSOC0 and the difference B1 from the SOC reference value SOC1. That is, the lower limit SOC (Min1) is a variable value calculated using the formula Min1=SOC1-ΔSOC0 / 2-B1.

[0053] On the other hand, if it is determined in step S207 of FIG. 9 that the difference B1 is greater than "SOC1-ΔSOC0 / 2," the process proceeds to step S211 of FIG. 9. In step S211, the range setting unit 35 determines the upper limit SOC (Max1) and the lower limit SOC (Min1) of the SOC range ΔSOC so that the upper limit SOC (Max1) is higher. In step S211, the range setting unit 35 fixes the value of the lower limit SOC (Min1) and sets the value of the upper limit SOC (Max) to be higher. That is, in step S211, the upper limit SOC (Max1) and the lower limit SOC (Min1) are set when the capacity maintenance rate SH1 in FIG. 5 is between the first reference maintenance rate SSH11 and the second reference maintenance rate SSH12. Here, the range setting unit 35 sets the value of the lower limit SOC (Min1) to 0%. The range setting unit 35 sets the upper limit SOC (Max1) to the value obtained by adding the difference B1 to the initial SOC range ΔSOC0. That is, the upper limit SOC (Max1) is a variable value calculated using the formula Max1 = ΔSOC0 + B1. In this way, the upper limit SOC (Max1) and lower limit SOC (Min1) of the SOC range ΔSOC can be set.

[0054] In this embodiment, the SOC range ΔSOC and the upper limit SOC (Max1) and lower limit SOC (Min1) of the SOC range ΔSOC can be set according to the outside air temperature T1. FIG. 10 is a diagram showing the relationship between the outside air temperature T1 and the SOC range ΔSOC. In FIG. 10, the horizontal axis represents the outside air temperature T1, and the outside air temperature T1 increases as the arrow moves (to the right in this case). As shown in FIG. 10, when the outside air temperature T1 is high, the range setting unit 35 in FIG. 2 decreases the upper limit SOC (Max1) and the lower limit SOC (Min1) by a fixed rate. On the other hand, when the outside air temperature T1 is low, the range setting unit 35 increases the upper limit SOC (Max1) and the lower limit SOC (Min1) by a fixed rate.

[0055] Here, for example, the upper limit SOC that takes into account the outside temperature T1 is referred to as the upper limit SOC(Max2), and the lower limit SOC that takes into account the outside temperature T1 is referred to as the lower limit SOC(Min2). The upper limit SOC(Max2) that takes into account the outside temperature T1 is calculated based on the upper limit SOC(Max1) that does not take into account the outside temperature T1, and is calculated, for example, by the following formula (1): Max2 = Max1 + a × T1 (1)

[0056] The lower limit SOC (Min2) that takes into account the outside temperature T1 is calculated based on the lower limit SOC (Min1) that does not take into account the outside temperature T1, and is calculated, for example, by the following equation (2). Min2 = Min1 + b × T1 (2)

[0057] Here, in equations (1) and (2), a and b represent coefficients, which may be negative or positive. The lower the outside air temperature T1, the larger the coefficients a and b are set. The coefficients a and b may be the same or different. In this embodiment, when the SOC range ΔSOC is changed and battery characteristics such as the voltage value and internal resistance of the power storage device 5 change depending on the SOC, the amount of power available within the SOC range ΔSOC changes. Therefore, it is preferable to determine the coefficients a and b taking these factors into consideration.

[0058] In the following description, the upper limit SOC (Max1) and the lower limit SOC (Min1) are described, but the upper limit SOC (Max1) can be replaced with the upper limit SOC (Max2), and the lower limit SOC (Min1) can be replaced with the lower limit SOC (Min2). In this embodiment, as shown in FIG. 10 , a first reference temperature ST1 and a second reference temperature ST2 are set for an outside air temperature T1. The first reference temperature ST1 is a reference value for increasing the upper limit SOC (Max1) and the lower limit SOC (Min1) when the outside air temperature T1 is low. The second reference temperature ST2 is a value higher than the first reference temperature ST1. The second reference temperature ST2 is a reference value for decreasing the upper limit SOC (Max1) and the lower limit SOC (Min1) when the outside air temperature T1 is high.

[0059] For example, when the outside air temperature T1 is equal to or greater than the first reference temperature ST1 and equal to or less than the second reference temperature ST2, the upper limit SOC (Max1) and lower limit SOC (Min1) of the SOC range ΔSOC are not changed, and the SOC range ΔSOC is set to approximately the medium SOC range ΔSC2. When the outside air temperature T1 is less than the first reference temperature ST1, the range setting unit 35 increases the upper limit SOC (Max1) and lower limit SOC (Min1) by the temperature difference ΔT10 without changing the width of the SOC range ΔSOC. This allows the SOC range ΔSOC to be shifted toward the high SOC range ΔSC3 when the outside air temperature T1 is less than the first reference temperature ST1. However, if increasing the upper limit SOC (Max1) by the temperature difference ΔT10 would exceed 100%, the upper limit SOC (Max1) is increased so that the upper limit SOC (Max1) becomes 100%. Then, the lower limit SOC (Min1) is increased by the amount that the upper limit SOC (Max1) is increased.

[0060] Furthermore, when the outside air temperature T1 is higher than the second reference temperature ST2, the range setting unit 35 lowers the upper limit SOC (Max1) and the lower limit SOC (Min1) by the temperature difference ΔT10 without changing the width of the SOC range ΔSOC. As a result, when the outside air temperature T1 is higher than the second reference temperature ST2, the SOC range ΔSOC can be shifted toward the low SOC range ΔSC1. However, if lowering the lower limit SOC (Min1) by the temperature difference ΔT10 would result in the SOC being below 0%, the range setting unit 35 lowers the lower limit SOC (Min1) so that the lower limit SOC (Min1) becomes 0%. The upper limit SOC (Max1) is then lowered by the amount that the lower limit SOC (Min1) was lowered.

[0061] As described above, in the present embodiment, in the range setting process, when the outside temperature T1 of the electric vehicle 6 equipped with the power storage device 5 is lower than the predetermined first reference temperature ST1, the upper limit SOC (Max1) and the lower limit SOC (Min1) are each increased. Specifically, in the range setting process, when the outside temperature T1 of the electric vehicle 6 is lower than the first reference temperature ST1, the upper limit SOC (Max1) and the lower limit SOC (Min1) are each increased by the predetermined temperature difference ΔT10. This allows the SOC range ΔSOC to be shifted toward the high SOC range ΔSC3 when the outside temperature T1 is low. When the outside temperature T1 is low, the power storage device 5 is less likely to deteriorate and the internal resistance of the power storage device 5 is likely to increase. As shown in FIGS. 7 and 8 , in the high SOC range ΔSC3, the capacity maintenance rate SH1 of the power storage device 5 tends to be relatively low and the resistance increase rate tends to be relatively high. Therefore, even if the SOC range ΔSOC is shifted toward the high SOC range ΔSC3 when the outside air temperature T1 is low, at which the storage device 5 is less likely to deteriorate, as in this embodiment, the storage device 5 can be made less likely to deteriorate than when the outside air temperature T1 is high.

[0062] In this embodiment, as shown in FIG. 10 , in the range setting process, when the outside air temperature T1 of the electric vehicle 6 is higher than a second reference temperature ST2, which is higher than the first reference temperature ST1, the upper limit SOC (Max1) and the lower limit SOC (Min1) are each lowered. Specifically, in the range setting process, when the outside air temperature T1 of the electric vehicle 6 is higher than the second reference temperature ST2, the upper limit SOC (Max1) and the lower limit SOC (Min1) are each lowered by a predetermined temperature difference ΔT10. This allows the SOC range ΔSOC to shift toward the low SOC range ΔSC1 when the outside air temperature T1 is high. When the outside air temperature T1 is high, the power storage device 5 is relatively susceptible to degradation. As shown in FIGS. 7 and 8 , in the low SOC range ΔSC1, the capacity maintenance rate SH1 of the power storage device 5 is less likely to decrease, and the power storage device 5 is less likely to degrade. Furthermore, in the low SOC range ΔSC1, the resistance increase rate can be suppressed. Therefore, as in this embodiment, when the outside air temperature T1 is high, by shifting the SOC range ΔSOC toward the low SOC range ΔSC1, deterioration of the power storage device 5 can be suppressed even when the outside air temperature T1 is high.

[0063] In this embodiment, the width of the SOC range ΔSOC may be changed according to the expected mileage D1 of the electric vehicle 6 for a predetermined period (for example, one day). The expected mileage D1 varies from day to day, for example. For one user, the expected mileage D1 may be shorter on weekdays and longer on holidays, while for another user, the expected mileage D1 may be longer on weekdays and shorter on holidays. Therefore, in this embodiment, when the expected mileage D1 is long, the range setting unit 35 in FIG. 2 may change the SOC range ΔSOC to be wider in order to increase the amount of electric power stored in the power storage device 5.

[0064] FIG. 11 shows the relationship between the estimated mileage D1 and the SOC range ΔSOC. In FIG. 11, the horizontal axis represents the estimated mileage D1, and the estimated mileage D1 increases as the arrow moves (to the right in this case). As shown in FIG. 11, for example, a reference distance SD1 is set in advance for the estimated mileage D1. The reference distance SD1 is a reference value that determines whether to widen the SOC range ΔSOC. For example, when the estimated mileage D1 is equal to or less than the reference distance SD1, the range setting unit 35 does not change the SOC range ΔSOC, and does not change the upper limit SOC (Max1) or the lower limit SOC (Min1). On the other hand, when the estimated mileage D1 is longer than the reference distance SD1, the range setting unit 35 changes the upper limit SOC (Max1) and the lower limit SOC (Min1) to widen the SOC range ΔSOC. The range setting unit 35 widens the SOC range ΔSOC by increasing the upper limit SOC (Max1) and lowering the lower limit SOC (Min1). Specifically, when the estimated travel distance D1 is longer than the reference distance SD1, the range setting unit 35 widens the SOC range ΔSOC by increasing the upper limit SOC (Max1) by the distance difference ΔD10 and lowering the lower limit SOC (Min1) by the distance difference ΔD10. However, if increasing the upper limit SOC (Max1) by the distance difference ΔD10 results in the upper limit SOC (Max1) exceeding 100%, the range setting unit 35 raises the upper limit SOC (Max1) so that it becomes 100%. Similarly, if decreasing the lower limit SOC (Min1) by the distance difference ΔD10 results in the lower limit SOC (Min1) becoming less than 0%, the range setting unit 35 lowers the lower limit SOC (Min1) so that it becomes 0%.

[0065] As described above, in the range setting process of this embodiment, as shown in FIG. 11 , when the estimated traveling distance D1 for a predetermined period of time of the electric vehicle 6 equipped with the power storage device 5 is longer than a predetermined reference distance SD1, the SOC range ΔSOC is widened. When the estimated traveling distance D1 is long, it is considered that a larger amount of electric power will be required. Therefore, when the estimated traveling distance D1 is long, by widening the SOC range ΔSOC, a larger amount of electric power can be charged to the power storage device 5. Therefore, even when the electric vehicle 6 attempts to travel the estimated traveling distance D1, the power storage device 5 can secure a sufficient amount of electric power, and the electric vehicle 6 can actually travel the estimated traveling distance D1.

[0066] In this embodiment, when the estimated travel distance D1 is longer than the reference distance SD1, the range setting process increases the upper limit SOC (Max1) by a predetermined distance difference ΔD10 and decreases the lower limit SOC (Min1) by the distance difference ΔD10. In this manner, the upper limit SOC (Max1) and the lower limit SOC (Min1) are increased or decreased by the same distance difference ΔD10, so that the SOC range ΔSOC can be widened while maintaining the SOC range ΔSOC in the middle SOC range ΔSC2 (see FIGS. 7 and 8). Therefore, even when the SOC range ΔSOC is widened, the power storage device 5 is relatively less susceptible to deterioration.

[0067] In this embodiment, as shown in FIG. 4, when the capacity maintenance ratio SH1 decreases, the lower limit SOC (Min1) is first lowered to widen the SOC range ΔSOC. Then, when the capacity maintenance ratio SH1 further decreases, the upper limit SOC (Max1) is increased to further widen the SOC range ΔSOC. However, as shown in the modified example of FIG. 12, when the capacity maintenance ratio SH1 decreases, the SOC range ΔSOC may be widened by both lowering the lower limit SOC (Min1) and increasing the upper limit SOC (Max1). For example, when the capacity maintenance ratio SH1 is equal to or less than the first reference maintenance ratio SSH11, the upper limit SOC (Max1) may be increased by the difference ΔS10 and the lower limit SOC (Min1) may be decreased by the difference ΔS10 to widen the SOC range ΔSOC from the initial SOC range ΔSOC0 to the first SOC range ΔSOC1. Furthermore, when the capacity maintenance rate SH1 is equal to or lower than the second standard maintenance rate SSH12, the upper limit SOC (Max1) may be further increased by the difference ΔS10 and the lower limit SOC (Min1) may be further decreased by the difference ΔS10, thereby widening the SOC range ΔSOC from the first SOC range ΔSOC1 to the second SOC range ΔSOC2.

[0068] In this embodiment, as shown in FIG. 5 , the lower limit SOC (Min1) starts to be lowered when the capacity maintenance rate SH1 is 100%, and the upper limit SOC (Max1) starts to be increased when the capacity maintenance rate SH1 is equal to the first reference maintenance rate SSH11. However, the timing to start lowering the lower limit SOC (Min1) may also be when the capacity maintenance rate SH1 is lower than 100%. The timing to start increasing the upper limit SOC (Max1) may also be when the capacity maintenance rate SH1 is higher than the first reference maintenance rate SSH11 or when it is lower than the first reference maintenance rate SSH11. For example, as shown in FIG. 13 , the timing to start lowering the lower limit SOC (Min1) may also be when the capacity maintenance rate SH1 is lower than 100% and higher than the first reference maintenance rate SSH11, which is timing SH21. The timing to start increasing the upper limit SOC(Max1) may be timing SH22 when the capacity maintenance rate SH1 is lower than the first reference maintenance rate SSH11 and higher than the second reference maintenance rate SSH12. Note that the timing SH22 may be higher than the first reference maintenance rate SSH11.

[0069] In this embodiment, as shown in FIG. 5 , the timing at which the lower limit SOC (Min1) starts to be lowered is different from the timing at which the upper limit SOC (Max1) starts to be increased. However, the timing at which the lower limit SOC (Min1) starts to be lowered and the timing at which the upper limit SOC (Max1) starts to be increased may be the same. For example, when the capacity maintenance rate SH1 reaches the first reference maintenance rate SSH11, the lower limit SOC (Min1) may start to be lowered and the upper limit SOC (Max1) may start to be increased. In this case, the amount of change in the upper limit SOC (Max1) and the amount of change in the lower limit SOC (Min1) may be relatively the same or different. For example, the amount of change in the upper limit SOC (Max1) may be relatively smaller than the amount of change in the lower limit SOC (Min1).

[0070] The present embodiment includes a computer program for power supply executed by the control device 30 of the power supply system 10. This computer program for power supply is a computer program executed by a computer that realizes the control device 30. The computer program for power supply is a program that causes the computer to execute a status acquisition process executed by the status acquisition unit 33, a range setting process executed by the range setting unit 35, and a power supply process executed by the power supply unit 37.

[0071] This embodiment also includes a power supply method. The power supply method includes a status acquisition step, a range setting step, and a power supply step. The status acquisition step is realized by a status acquisition process executed by the status acquisition unit 33. The range setting step is realized by a range setting process executed by the range setting unit 35. The power supply step is realized by a power supply process executed by the power supply unit 37.

[0072] The invention disclosed herein has been described in various ways. Unless otherwise specified, the embodiments described herein do not limit the present invention. Furthermore, the embodiments of the invention disclosed herein can be modified in various ways, and each component and each process described herein can be omitted or combined as appropriate, unless a particular problem arises.

[0073] As described above, this specification includes the disclosures set forth in the following sections. Section 1: a status acquisition process for acquiring a capacity maintenance rate of a vehicle power storage device; a range setting process for setting an SOC range so as to widen a chargeable SOC range for the power storage device when the capacity maintenance rate is equal to or lower than a predetermined reference maintenance rate, based on the capacity maintenance rate acquired in the state acquisition process; a power supply process for controlling a charging / discharging device that supplies power to the power storage device so that the SOC of the power storage device is within the SOC range set in the range setting process; A computer program for power supply that causes a computer to execute the following.

[0074] Section 2: Item 2. The computer program for power supply according to item 1, wherein, in the range setting process, when the capacity maintenance rate is equal to or lower than the reference maintenance rate, the SOC range is set so that an upper limit SOC, which is an upper limit of the SOC range, is high.

[0075] Section 3: Item 3. The computer program for power supply according to item 1 or 2, wherein, in the range setting process, when the capacity maintenance rate is equal to or lower than the reference maintenance rate, the SOC range is set so that a lower limit SOC, which is a lower limit of the SOC range, is low.

[0076] Section 4: The standard maintenance rate is The first standard maintenance rate, a second standard maintenance rate lower than the first standard maintenance rate; and In the range setting process, When the capacity maintenance rate is equal to or lower than the first reference maintenance rate, the SOC range is set so that a lower limit SOC, which is the lower limit of the SOC range, is low; 4. The computer program for power supply according to any one of items 1 to 3, wherein when the capacity maintenance rate is equal to or lower than the second reference maintenance rate, the SOC range is set so that an upper limit SOC, which is an upper limit of the SOC range, is increased.

[0077] Section 5: In the range setting process, the SOC range is set so that, in a range in which the capacity maintenance rate is greater than the first reference maintenance rate, the lower limit SOC becomes lower as the capacity maintenance rate approaches the first reference maintenance rate; Item 5. The computer program for power supply according to item 4, wherein the SOC range is set such that, in the range of the capacity maintenance rate between the first reference maintenance rate and the second reference maintenance rate, the upper limit SOC becomes higher as the capacity maintenance rate approaches the second reference maintenance rate.

[0078] Item 6: 6. The computer program for power supply according to any one of items 1 to 5, wherein in the range setting process, when the outside air temperature of the electric vehicle equipped with the power storage device is lower than a predetermined first reference temperature, the upper limit SOC and the lower limit SOC are each increased.

[0079] Section 7: Item 7. The computer program for power supply according to item 6, wherein, in the range setting process, when the outside air temperature of the electric vehicle is lower than the first reference temperature, the upper limit SOC and the lower limit SOC are each increased by a predetermined temperature difference.

[0080] Section 8: Item 8. The computer program for power supply according to item 6 or 7, wherein in the range setting process, when the outside air temperature of the electric vehicle is higher than a second reference temperature that is higher than the first reference temperature, the upper limit SOC and the lower limit SOC are each lowered.

[0081] Section 9: Item 9. The computer program for power supply according to item 8, wherein, in the range setting process, when the outside air temperature of the electric vehicle is higher than the second reference temperature, the upper limit SOC and the lower limit SOC are each lowered by a predetermined temperature difference.

[0082] Section 10: 10. The computer program for power supply according to any one of items 1 to 9, wherein in the range setting process, when an expected travel distance of an electric vehicle equipped with the power storage device in a predetermined period is longer than a predetermined reference distance, the SOC range is widened.

[0083] Section 11: Item 11. The computer program for power supply according to item 10, wherein, in the range setting process, when the predicted mileage is longer than the reference distance, the upper limit SOC is increased by a predetermined distance difference and the lower limit SOC is decreased by the distance difference.

[0084] Section 12: A control device that executes a computer program for power supply according to any one of items 1 to 11; a vehicle power storage device; a charging / discharging device that supplies power to the power storage device; A power supply system comprising:

[0085] Section 13: a status acquisition step of acquiring a capacity maintenance rate of the vehicle power storage device; a range setting step of setting, based on the capacity maintenance rate acquired in the state acquisition step, an SOC range so as to widen a chargeable SOC range for the power storage device when the capacity maintenance rate is equal to or lower than a predetermined reference maintenance rate; a power supply step of controlling a charging / discharging device that supplies power to the power storage device so that the SOC of the power storage device falls within the SOC range set in the range setting step; A power supply method comprising: [Explanation of symbols]

[0086] 5. Energy storage device 6 Electric vehicles 10 Power Supply System 20 Charge / discharge device 30 Control device 31 Storage section 33 Status acquisition unit 35 Range setting section 37 Power supply section D1 Estimated mileage SD1 Reference Distance Max1 Upper limit SOC Min1 Lower limit SOC SH1 capacity maintenance rate SSH1 standard maintenance rate SSH11 1st standard maintenance rate SSH12 2nd standard maintenance rate T1 Outside temperature ST1 1st reference temperature ST2 2nd reference temperature ΔSOC SOC range

Claims

1. a status acquisition process for acquiring a capacity maintenance rate of a vehicle power storage device; a range setting process of setting an SOC range based on the capacity maintenance rate acquired in the state acquisition process, when the capacity maintenance rate is equal to or lower than a predetermined reference maintenance rate, so as to widen an SOC range within which the power storage device can be charged; a power supply process for controlling a charging / discharging device that supplies power to the power storage device so that the SOC of the power storage device falls within the SOC range set in the range setting process; on the computer, The standard maintenance rate is A first standard maintenance rate; and a second standard maintenance rate lower than the first standard maintenance rate; and In the range setting process, When the capacity maintenance rate is equal to or lower than the first reference maintenance rate, the SOC range is set so that a lower limit SOC that is a lower limit of the SOC range is lowered; a computer program for supplying electric power that sets the SOC range so that an upper limit SOC that is an upper limit of the SOC range is high when the capacity maintenance rate is equal to or lower than the second reference maintenance rate;

2. In the range setting process, setting the SOC range so that, in a range in which the capacity maintenance rate is greater than the first reference maintenance rate, the lower limit SOC becomes lower as the capacity maintenance rate approaches the first reference maintenance rate; 2. The computer program for power supply according to claim 1, wherein the SOC range is set such that, in a range between the first reference maintenance rate and the second reference maintenance rate, the upper limit SOC becomes higher as the capacity maintenance rate approaches the second reference maintenance rate.

3. a status acquisition process for acquiring a capacity maintenance rate of a vehicle power storage device; a range setting process of setting an SOC range based on the capacity maintenance rate acquired in the state acquisition process, when the capacity maintenance rate is equal to or lower than a predetermined reference maintenance rate, so as to widen an SOC range within which the power storage device can be charged; a power supply process for controlling a charging / discharging device that supplies power to the power storage device so that the SOC of the power storage device falls within the SOC range set in the range setting process; on the computer, In the range setting process, when the outside air temperature of the electric vehicle equipped with the power storage device is lower than a predetermined first reference temperature, an upper limit SOC that is the upper limit of the SOC range and a lower limit SOC that is the lower limit of the SOC range are increased.

4. 4. The computer program for power supply according to claim 3, wherein, in the range setting process, when the outside air temperature of the electric vehicle is lower than the first reference temperature, the upper limit SOC and the lower limit SOC are each increased by a predetermined temperature difference.

5. 4. The computer program for power supply according to claim 3, wherein, in the range setting process, when the outside air temperature of the electric vehicle is higher than a second reference temperature that is higher than the first reference temperature, each of the upper limit SOC and the lower limit SOC is lowered.

6. 6. The computer program for power supply according to claim 5, wherein, in the range setting process, when the outside air temperature of the electric vehicle is higher than the second reference temperature, the upper limit SOC and the lower limit SOC are each lowered by a predetermined temperature difference.

7. a status acquisition process for acquiring a capacity maintenance rate of a vehicle power storage device; a range setting process of setting an SOC range based on the capacity maintenance rate acquired in the state acquisition process, when the capacity maintenance rate is equal to or lower than a predetermined reference maintenance rate, so as to widen an SOC range within which the power storage device can be charged; a power supply process for controlling a charging / discharging device that supplies power to the power storage device so that the SOC of the power storage device falls within the SOC range set in the range setting process; on the computer, In the range setting process, the computer program for power supply widens the SOC range when an expected travel distance of an electric vehicle equipped with the power storage device in a predetermined period is longer than a predetermined reference distance.

8. 8. The computer program for power supply according to claim 7, wherein, in the range setting process, when the predicted mileage is longer than the reference distance, an upper limit SOC that is an upper limit of the SOC range is increased by a predetermined distance difference, and a lower limit SOC that is a lower limit of the SOC range is decreased by the distance difference.

9. a control device that executes a computer program for power supply according to any one of claims 1 to 8; a vehicle power storage device; a charging / discharging device that supplies power to the power storage device; A power supply system comprising:

10. a status acquisition step of acquiring a capacity maintenance rate of the vehicle power storage device; a range setting step of setting an SOC range based on the capacity maintenance rate acquired in the state acquisition step, when the capacity maintenance rate is equal to or lower than a predetermined reference maintenance rate, so as to widen an SOC range within which the power storage device can be charged; a power supply step of controlling a charge / discharge device that supplies power to the power storage device so that the SOC of the power storage device falls within the SOC range set in the range setting step; It encompasses The standard maintenance rate is A first standard maintenance rate; and a second standard maintenance rate lower than the first standard maintenance rate; and In the range setting step, When the capacity maintenance rate is equal to or lower than the first reference maintenance rate, the SOC range is set so that a lower limit SOC that is a lower limit of the SOC range is lowered; When the capacity maintenance rate is equal to or lower than the second reference maintenance rate, the SOC range is set so that an upper limit SOC that is an upper limit of the SOC range is increased.

11. a status acquisition step of acquiring a capacity maintenance rate of the vehicle power storage device; a range setting step of setting an SOC range based on the capacity maintenance rate acquired in the state acquisition step, when the capacity maintenance rate is equal to or lower than a predetermined reference maintenance rate, so as to widen an SOC range within which the power storage device can be charged; a power supply step of controlling a charge / discharge device that supplies power to the power storage device so that the SOC of the power storage device falls within the SOC range set in the range setting step; It encompasses In the range setting step, when the outside air temperature of the electric vehicle equipped with the power storage device is lower than a predetermined first reference temperature, an upper limit SOC that is the upper limit of the SOC range and a lower limit SOC that is the lower limit of the SOC range are each increased.

12. a status acquisition step of acquiring a capacity maintenance rate of the vehicle power storage device; a range setting step of setting an SOC range based on the capacity maintenance rate acquired in the state acquisition step, when the capacity maintenance rate is equal to or lower than a predetermined reference maintenance rate, so as to widen an SOC range within which the power storage device can be charged; a power supply step of controlling a charge / discharge device that supplies power to the power storage device so that the SOC of the power storage device falls within the SOC range set in the range setting step; It encompasses In the range setting step, the SOC range is widened when an expected travel distance of an electric vehicle equipped with the power storage device in a predetermined period is longer than a predetermined reference distance.

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