Battery Management System

Abstract

To provide a storage battery management system that allows a large amount of compensation to be obtained while taking into consideration the remaining life of a storage battery. [Solution] The battery management system 10 includes a life estimation unit 12 that estimates the remaining life of the battery 4 until it reaches its end of life when the battery 4 is charged and discharged under multiple types of charge and discharge conditions; an income derivation unit 15 that derives the unit income that will be obtained when the battery 4 is charged and discharged under multiple types of charge and discharge conditions in order to contribute to the supply and demand of electricity in the power grid 1; a cost derivation unit 13 that derives the unit cost when the battery 4 is charged and discharged under multiple types of charge and discharge conditions during the remaining life when the battery 4 reaches its end of life; and a charge and discharge condition determination unit 17 that determines the charge and discharge conditions that will maximize the profit obtained by subtracting the unit cost from the unit income under each charge and discharge condition as the target charge and discharge condition.

Description

[Technical Field]

[0001] The present invention relates to a battery management system that manages a battery connected to a power grid. [Background technology]

[0002] Patent Document 1 (JP 2013-168010 A) describes that a power control system equipped with a storage battery receives payment for providing ancillary services in a power grid by charging and discharging the storage battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-168010 Summary of the Invention [Problem to be solved by the invention]

[0004] Storage batteries have the advantage that they can increase or decrease output more quickly than generators, making them useful in situations where a sudden increase or decrease in output is required.

[0005] However, if the battery experiences a sudden increase or decrease in output (i.e., sudden charging or discharging) or if it is charged or discharged in high or low temperature environments, the deterioration of the battery will be accelerated, shortening its remaining lifespan.

[0006] The present invention has been made in consideration of the above-mentioned problems, and its purpose is to provide a battery management system that enables a high return to be obtained while taking into account the remaining life of the battery. [Means for solving the problem]

[0007] A characteristic configuration of a storage battery management system according to the present invention for achieving the above object is a storage battery management system that manages storage batteries that can be connected to a power grid, a battery information acquisition unit that acquires battery information indicating a state of the battery; a lifespan estimation unit that estimates a remaining lifespan of the storage battery until the end of the lifespan that will be generated in the storage battery when the storage battery is charged and discharged under each of a plurality of types of charge and discharge conditions, based on the storage battery information acquired by the storage battery information acquisition unit; an income deriving unit that derives a unit income per predetermined unit that is obtained when the storage battery is charged and discharged under each of the plurality of types of charge and discharge conditions in order to contribute to the supply and demand of electricity in the power grid; a cost derivation unit that derives a unit cost per predetermined unit when the storage battery is charged and discharged under each of the plurality of types of charge and discharge conditions during the remaining life of the storage battery, based on an operating cost required for operating the storage battery; and The system is characterized by being equipped with a charge / discharge condition determination unit that determines, from among the multiple types of charge / discharge conditions, the charge / discharge condition that results in the greatest profit obtained by subtracting the unit cost from the unit income under each charge / discharge condition as the target charge / discharge condition.

[0008] According to the above characteristic configuration, the life estimation unit estimates the remaining life of the storage battery until it reaches its end of life when the storage battery is charged and discharged under each of multiple types of charge and discharge conditions, the income derivation unit derives the unit income per predetermined unit that will be obtained when the storage battery is charged and discharged under each of multiple types of charge and discharge conditions in order to contribute to the supply and demand of electricity in the power grid, the cost derivation unit derives the unit cost per predetermined unit when the storage battery is charged and discharged under each of multiple types of charge and discharge conditions during the remaining life until it reaches its end of life, based on the operating costs required to operate the storage battery, and the charge and discharge condition determination unit determines as the target charge and discharge condition the charge and discharge condition that will result in the greatest profit obtained by subtracting the unit cost from the unit income under each charge and discharge condition, from among the multiple types of charge and discharge conditions. Therefore, it is possible to provide a storage battery management system that allows a large amount of compensation to be obtained while taking into consideration the remaining life of the storage battery.

[0009] Here, the life estimation unit may estimate the remaining life under each of the plurality of types of charging and discharging conditions by determining that the time at which the storage battery will deteriorate when it is charged or discharged and the capacity maintenance rate of the storage battery is estimated to fall to a predetermined threshold is the time at which the storage battery will reach the end of its life. Alternatively, the life estimation unit may estimate the remaining life under each of the plurality of types of charge / discharge conditions by referring to the results of a durability test that measures the state of the storage battery when the storage battery is charged / discharged and left unused. Alternatively, the life estimation unit may estimate the remaining life under each of the plurality of types of charge / discharge conditions using a remaining life estimation model based on a result of executing machine learning. Alternatively, the life estimation unit may estimate the remaining life under each of the plurality of types of charge / discharge conditions using a remaining life estimation model based on a root rule.

[0010] Here, the cost derivation unit may derive the unit cost by dividing the operating cost by the remaining lifespan. Alternatively, the cost derivation unit may derive the unit cost by multiplying the operating cost by the ratio of the decrease in the remaining life, which corresponds to the decrease in the capacity maintenance rate that occurs when the storage battery is charged and discharged under specified charge and discharge conditions, to the remaining life. Alternatively, the cost derivation unit derives the unit cost by multiplying the operating cost by the ratio of the area surrounded by the amount of decrease in the capacity retention rate that occurs when the storage battery is charged and discharged under specified charge and discharge conditions and the change curve of the capacity retention rate to the total area surrounded by the change curve of the capacity retention rate of the storage battery.

[0011] Another characteristic configuration of the battery management system of the present invention is that it includes a charge / discharge condition output unit that outputs the target charge / discharge conditions to the battery and causes the battery to charge / discharge in accordance with the target charge / discharge conditions.

[0012] According to the above characteristic configuration, it is possible to cause the storage battery to perform charging and discharging in accordance with the target charging and discharging conditions.

[0013] Another characteristic feature of the battery management system according to the present invention is that, among the plurality of types of charging and discharging conditions, the unit income is set to be smaller for a charging and discharging condition that results in a longer remaining life.

[0014] According to the above characteristic configuration, the battery management system can be operated taking into consideration that the greater the advantage of a charge / discharge condition, that is, a longer remaining lifespan, the greater the disadvantage of a charge / discharge condition, that is, a smaller unit income obtained when contributing to the supply and demand of electricity in the power system under that charge / discharge condition, and the greater the disadvantage of a charge / discharge condition, that is, a shorter remaining lifespan, the greater the advantage of a charge / discharge condition, that is, a larger unit income obtained when contributing to the supply and demand of electricity in the power system under that charge / discharge condition. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a diagram illustrating a configuration of a power system in which a battery management system is provided. [Figure 2] 10 shows an example of information about a storage battery when the storage battery is charged and discharged under each of a plurality of types of charge and discharge conditions. [Figure 3] 10 is a graph showing an example of a curve of change in SOH when a storage battery is charged and discharged under each of a plurality of types of charge and discharge conditions. [Figure 4] FIG. 10 is a diagram showing an example of unit income per charge / discharge cycle when contributing to the supply and demand of electricity in the power grid under each of a plurality of types of charge / discharge conditions. [Figure 5] 1 is a graph showing an example of a change curve of SOH. [Figure 6] 1 is a graph showing an example of a change curve of SOH. DETAILED DESCRIPTION OF THE INVENTION

[0016] A battery management system 10 according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the configuration of an electric power system in which a battery management system 10 is installed. The battery management system 10 manages batteries 4 connected to an electric power grid 1. As shown in the figure, electric loads 3 and batteries 4 installed in facilities 2 such as residences and offices can be connected to the electric power grid 1. Although three facilities 2 (2A, 2B, and 2C) are shown in FIG. 1, the number of facilities 2 can be set as appropriate. The battery management system 10 can communicate information with the facilities 2 via an information and communication network 5. A market information provider 6 is also connected to the information and communication network 5.

[0017] The storage battery 4 can be realized using a device having a stationary storage battery 4 installed in the facility 2, or a device having a mobile storage battery, such as a storage battery 4 mounted on an electric vehicle 9 that can be connected to the power grid 1 at the facility 2. In the example shown in FIG. 1 , the storage batteries 4 installed in the facilities 2A and 2B are stationary storage batteries, and these storage batteries 4 are connected to the power grid 1. The storage battery 4 installed in the facility 2C is a storage battery mounted on an electric vehicle 9, such as an electric vehicle, a plug-in hybrid vehicle, or a fuel cell vehicle, and this storage battery 4 is connected to the power grid 1 via a charge / discharge control device 7 installed in the facility 2C. The storage battery 4 can be realized using various batteries, such as lithium-ion batteries, nickel-metal hydride batteries, NAS (sodium-sulfur) batteries, and lead-acid batteries.

[0018] If the storage battery 4 is a stationary storage battery, the storage battery 4 can be operated by, for example, charging it late at night and discharging it during the daytime so that the power is consumed by the power load 3. The storage battery 4 can also be charged and discharged to contribute to the supply and demand of power in the power grid 1. In this case, the storage battery 4 can be charged and discharged in accordance with target charge and discharge conditions according to charge and discharge instructions received from the battery management system 10 via the information and communication network 5.

[0019] When the storage battery 4 is a storage battery mounted on an electric vehicle 9, if a terminal 8 connected to a cable 7a connected to the charge / discharge control device 7 of the facility 2C is connected to a charge / discharge terminal (not shown) of the electric vehicle 9, that is, if the storage battery 4 of the electric vehicle 9 is interconnected to the power grid 1, the charge / discharge control device 7 of the facility 2C can control charging / discharging from the power grid 1 to the storage battery 4 and discharging from the storage battery 4 to the power load 3 of the facility 2C and the power grid 1. The charge / discharge control device 7 can also cause charging / discharging of the storage battery 4 of the electric vehicle 9 in accordance with target charge / discharge conditions according to charge / discharge instructions received from the battery management system 10 via the information and communications network 5.

[0020] The battery management system 10 includes a battery information acquisition unit 11, a lifespan estimation unit 12, an income derivation unit 15, a cost derivation unit 13, and a charge / discharge condition determination unit 17. In addition, the battery management system 10 of this embodiment includes a market information acquisition unit 14, an information storage unit 16 that stores information handled by the battery management system 10, and a charge / discharge condition output unit 18.

[0021] The storage battery information acquisition unit 11 acquires storage battery information indicating the state of the storage battery 4. For example, the storage battery information acquisition unit 11 continuously acquires, at predetermined timings, storage battery information indicating the state of the storage battery 4, such as the voltage, current, and temperature during actual charging and discharging. This storage battery information can be used to estimate the current state of the storage battery 4 (e.g., the cumulative number of charge and discharge cycles, the current state of charge of the storage battery 4, the full charge capacity, the positive electrode capacity, the negative electrode capacity, the capacity deviation, the internal resistance value, the cumulative usage time, and other conditions). When the storage battery 4 is mounted on an electric vehicle 9, the storage battery information acquisition unit 11 can acquire, for example, from the charge and discharge control device 7, the storage battery information that the charge and discharge control device 7 has collected from the storage battery 4 of the electric vehicle 9.

[0022] Based on the storage battery information acquired by the storage battery information acquisition unit 11, the life estimation unit 12 estimates the remaining life of the storage battery 4 until it reaches its end of life when the storage battery 4 is charged and discharged under each of a plurality of charge and discharge conditions. For example, the remaining life can be the number of remaining cycles, which is the number of charge and discharge cycles until it reaches its end of life, the remaining usage time, which is the usage time until it reaches its end of life, and the remaining battery capacity, which is the battery capacity until it reaches its end of life (e.g., the difference between the current fully charged capacity and a threshold fully charged capacity). Here, the remaining usage time can be calculated by "number of remaining cycles × 24 hours (hours per day) = remaining usage time" if the battery is used for only one cycle per day. Furthermore, the remaining battery capacity can be calculated by "number of remaining cycles × 100 Ah = remaining battery capacity" if a capacity (current × time) of 100 Ah can be charged and discharged per charge and discharge cycle.

[0023] As a specific example, the life estimation unit 12 estimates the remaining life under each of a plurality of charge / discharge conditions, assuming that the time when the capacity maintenance rate (SOH) of the storage battery 4 is estimated to decrease to a predetermined threshold value when the storage battery 4 is repeatedly charged and discharged is the time when the storage battery 4 reaches the end of its life. The SOH is expressed as a ratio of the current full charge capacity to the initial full charge capacity. The initial full charge capacity of the storage battery 4 is stored in the information storage unit 16. For example, when the remaining cycle number, which is the number of charge / discharge cycles until the end of its life, is defined as the remaining life, the life estimation unit 12 refers to the current state of the storage battery 4, which can be estimated based on the storage battery information acquired by the storage battery information acquisition unit 11, and estimates the remaining life under each of a plurality of charge / discharge conditions as the remaining cycle number, which is the number of charge / discharge cycles until the capacity maintenance rate of the storage battery 4 is estimated to decrease to a predetermined threshold value when the storage battery 4 is subsequently charged / discharged. The charge / discharge condition is, for example, an output (e.g., C rate) when charging / discharging the storage battery 4. The charge / discharge conditions are not limited to being determined by the C rate alone, and may include various other conditions.

[0024] Fig. 2 shows information about the storage battery 4 when the storage battery 4 is charged and discharged under each of a plurality of types of charge and discharge conditions. Fig. 3 shows a graph showing an example of a curve of change in SOH when the storage battery 4 is charged and discharged under each of a plurality of types of charge and discharge conditions.

[0025] In the example shown in Fig. 2, charging and discharging condition A is when charging and discharging are performed at a C rate of 0.2C, and the temperature of the storage battery 4 is assumed to be 25°C. Charging and discharging condition B is when charging and discharging are performed at a C rate of 0.5C, and the temperature of the storage battery 4 is assumed to be 30°C. Charging and discharging condition C is when charging and discharging are performed at a C rate of 1C, and the temperature of the storage battery 4 is assumed to be 40°C. Although three types of charging and discharging conditions are shown here as examples, the number of charging and discharging conditions can be changed as appropriate.

[0026] The lifespan estimation unit 12 then estimates a change curve of the SOH when the storage battery 4 is charged and discharged under each of a plurality of types of charge and discharge conditions as shown in Fig. 3. The example shown in Fig. 3 is an example of a change curve of the SOH when the storage battery 4 is charged and discharged under each of a plurality of types of charge and discharge conditions A, B, and C, starting from a point when the SOH is 100%. For example, the lifespan estimation unit 12 estimates a change curve of the SOH versus the number of charge and discharge cycles when the storage battery 4 is charged and discharged under each of a plurality of types of charge and discharge conditions, from the initial full charge capacity stored in the information storage unit 16 and a predicted change curve of the full charge capacity predicted when the storage battery 4 is charged and discharged under each of a plurality of types of charge and discharge conditions, which is derived based on the storage battery information acquired from the facility 2.

[0027] Then, the life estimation unit 12 estimates the number of remaining cycles, which is the number of charge / discharge cycles until the SOH reaches a predetermined SOH threshold (i.e., the end of the life of the storage battery 4). The SOH threshold is a value that is set appropriately. In the example shown in FIG. 2, the number of remaining cycles under charge / discharge condition A is Xa, the number of remaining cycles under charge / discharge condition B is Xb, and the number of remaining cycles under charge / discharge condition C is Xc. In other words, when charge / discharge is performed at rate C (0.2C) under charge / discharge condition A, it is estimated that the SOH will reach the SOH threshold when the charge / discharge cycles of the storage battery 4 reach Xa.

[0028] The remaining life estimation method performed by the life estimation unit 12 is not limited to the above-described one. For example, the life estimation unit 12 can estimate the remaining life of the storage battery 4 using a life estimation method that utilizes durability test data, a life estimation method based on machine learning, a life estimation method that uses a root rule, or the like, as described below.

[0029] When the life estimation unit 12 uses a life estimation method utilizing durability test data, it estimates the remaining life under each of a plurality of types of charge / discharge conditions by referring to the results of a durability test that measures the state of the storage battery 4 when the storage battery 4 is charged / discharged and left unused. For example, durability tests such as a cycle test that measures the state of the storage battery 4 after charging / discharging under a plurality of types of charge / discharge conditions and a storage test that measures the state of the storage battery 4 after leaving the storage battery 4 in a predetermined environment are performed in advance, and the test results are stored in the information storage unit 16. Then, the life estimation unit 12 estimates the transition of the state of the storage battery 4 when the storage battery 4 is subsequently charged / discharged under a plurality of types of charge / discharge conditions based on the current state of the storage battery 4 that can be estimated based on the storage battery information acquired by the storage battery information acquisition unit 11 and the test results, and determines the remaining life until the state of the storage battery 4 reaches a predetermined threshold (for example, the threshold number of charge / discharge cycles, the threshold usage time, or the threshold battery capacity (which may be converted to a full charge capacity or SOH)).

[0030] When the lifespan estimation unit 12 uses a lifespan estimation method based on machine learning, it can estimate the remaining lifespan under each of a plurality of types of charge / discharge conditions using a remaining lifespan estimation model based on the results of the machine learning. For example, the information storage unit 16 stores training data consisting of a combination of a history of charging and discharging of the storage battery 4 under a plurality of types of charge / discharge conditions and the remaining lifespan for the charge / discharge history, and stores a remaining lifespan estimation model based on the results of the machine learning. Then, the lifespan estimation unit 12 estimates the remaining lifespan until the state of the storage battery 4 reaches a predetermined threshold (e.g., a threshold number of charge / discharge cycles, a threshold usage time, or a threshold battery capacity (which may be converted to a full charge capacity or SOH)) when the storage battery 4 is subsequently charged and discharged under a plurality of types of charge / discharge conditions, using the current state of the storage battery 4, which can be estimated based on the storage battery information acquired by the storage battery information acquisition unit 11, and the remaining lifespan estimation model based on the results of the machine learning.

[0031] When the life estimation unit 12 uses a life estimation method using a root law that assumes that Li consumption due to the formation of an SEI (solid electrolyte interface) film governs the remaining life of the storage battery 4, the remaining life can be estimated under each of a plurality of types of charge / discharge conditions using a remaining life estimation model based on the root law. For example, the information storage unit 16 stores a remaining life estimation model based on the root law that states that the capacity of the storage battery 4 decreases in proportion to the ½ power of time (i.e., the remaining life shortens). The life estimation unit 12 then estimates the remaining life until the state of the storage battery 4 reaches a predetermined threshold (e.g., a threshold number of charge / discharge cycles, a threshold usage time, or a threshold battery capacity (which may be converted to a full charge capacity or SOH)) when the storage battery 4 is subsequently charged / discharged under a plurality of types of charge / discharge conditions, using the current state of the storage battery 4, which can be estimated based on the storage battery information acquired by the storage battery information acquisition unit 11, and the remaining life estimation model.

[0032] The income derivation unit 15 derives the unit income per predetermined unit (e.g., income per one or more charge / discharge cycles, income per unit usage time, etc.) obtained when the storage battery 4 is charged / discharged under each of multiple types of charge / discharge conditions in order to contribute to the supply and demand of electricity in the power system 1.

[0033] As a specific example, the income deriving unit 15 derives a unit income per predetermined number of charge / discharge cycles (e.g., one or more) obtained when the storage battery 4 is charged / discharged under each of a plurality of charge / discharge conditions to contribute to the supply and demand of electricity in the power grid 1. For example, the market information acquiring unit 14 acquires information on bids for electricity products and information on their prices from a market information providing device 6 that manages information on the Japan Electric Power Exchange (JEPX), the supply and demand balancing market operated by general electricity transmission and distribution companies, the capacity market, etc. In other words, the market information acquiring unit 14 acquires information on income that can be obtained when the facility 2 provides electricity, balancing capacity, etc. to the power grid 1. Note that the market information providing device 6 may be realized by a plurality of devices, such as a device that manages information on JEPX, a device that manages information on the supply and demand balancing market, and a device that manages information on the capacity market.

[0034] For example, products traded in the power adjustment market are specified with regulated response time, duration, minimum bid amount, bid unit, price, etc., which determine under what charge / discharge conditions the storage battery 4 can respond (sell bid) to each product. The income derivation unit 15 then matches, among the multiple types of charge / discharge conditions, which charge / discharge conditions the storage battery 4 can provide the power, regulation capacity, etc. corresponding to the above-mentioned product, and derives the unit income per charge / discharge cycle obtained when the storage battery 4 is charged / discharged under each of the multiple types of charge / discharge conditions for which matching has been established, by referring to the above-mentioned price information.

[0035] Among the multiple types of charge / discharge conditions described above, if the charge / discharge condition that results in a longer remaining life is set to have a smaller unit income, the storage battery 4 can increase or decrease its output faster than a generator, making it useful in situations where a sudden increase or decrease in output is necessary, and thus can obtain a correspondingly larger compensation (income). However, if the storage battery 4 suddenly increases or decreases its output (i.e., suddenly charges or discharges), there is a problem that the remaining life of the storage battery 4 until it reaches its end of life is shortened. Therefore, among the multiple types of charge / discharge conditions, the charge / discharge condition that results in a longer remaining life may be set to have a smaller unit income per predetermined unit. In this case, the greater the advantage of a charge / discharge condition that results in a longer remaining life, the greater the disadvantage of a smaller unit income per predetermined unit obtained when contributing to the power supply and demand in the power grid 1 under that charge / discharge condition. On the other hand, the greater the disadvantage of a shorter remaining life, the greater the advantage of a charge / discharge condition that results in a larger unit income per predetermined unit obtained when contributing to the power supply and demand in the power grid 1 under that charge / discharge condition.

[0036] FIG. 4 shows an example of unit revenue per charge / discharge cycle when contributing to the power supply and demand in the power grid 1 under each of multiple charge / discharge conditions. Note that FIG. 4 shows unit revenue per unit of energy (1 kWh). As shown, for each of charge / discharge conditions A to C, similar to those shown in FIG. 2, the unit revenue per charge / discharge cycle when contributing to the power supply and demand in the power grid 1 is derived. For example, for charge / discharge condition A, the unit revenue per charge / discharge cycle when contributing to the power supply and demand in the power grid 1 is Za2 (yen / (kWh·charge cycle)), for charge / discharge condition B it is Zb2 (yen / (kWh·charge cycle)), and for charge / discharge condition C it is Zc2 (yen / (kWh·charge cycle)). In this example, the relationship between the number of charge / discharge cycles (remaining life) until the SOH threshold is "Xa > Xb > Xc," and the relationship between unit revenue is "Zc2 > Zb2 > Za2."

[0037] The cost derivation unit 13 derives, based on the operating costs required to operate the storage battery 4, the unit cost per predetermined unit (for example, the unit cost per predetermined number of charge / discharge cycles, such as one or more, the unit cost per unit usage time, the unit cost per predetermined battery capacity, etc.) when the storage battery 4 is charged / discharged under each of a plurality of types of charge / discharge conditions during the remaining life of the storage battery 4.

[0038] As a specific example, the cost derivation unit 13 derives a unit cost per predetermined number of charge / discharge cycles when the storage battery 4 is charged / discharged under each of a plurality of types of charge / discharge conditions until the end of the life of the storage battery 4, which is obtained by dividing the operating cost by the number of remaining cycles. The costs related to the storage battery 4 to be included in the operating cost can be set as appropriate, and information on the operating costs is stored in the information storage unit 16. For example, the operating cost may include all costs required to purchase the storage battery 4, install it in the facility 2, and continue charging / discharging while performing maintenance. Therefore, the operating cost is the same for each of the plurality of types of charge / discharge conditions, and is Y (yen / kWh) in FIG. 2. Note that in FIG. 2, the operating cost is shown as a value per unit of power (1 kWh).

[0039] As shown in Figure 2, under charge / discharge condition A, the number of remaining cycles is Xa, so the unit cost Za1 per charge / discharge cycle until the end of the battery's life is Y / Xa (yen / (kWh·charge / discharge cycle)). Under charge / discharge condition B, the number of remaining cycles is Xb, so the unit cost Zb1 per charge / discharge cycle until the end of the battery's life is Y / Xb (yen / (kWh·charge / discharge cycle)). Under charge / discharge condition C, the number of remaining cycles is Xc, so the unit cost Zc1 per charge / discharge cycle until the end of the battery's life is Y / Xc (yen / (kWh·charge / discharge cycle)). Note that in Figure 2, the unit cost is shown as a value per unit of energy (1 kWh).

[0040] The cost derivation method performed by the cost derivation unit 13 is not limited to the above-described method. For example, the cost derivation unit 13 may derive the cost using the number of charge / discharge cycles or the area of ​​the reduced SOH amount, as described below.

[0041] FIG. 5 is a graph showing an example of a curve of change in SOH when the storage battery 4 is charged and discharged. This graph will be used to explain a cost derivation method using the number of charge and discharge cycles. FIG. 5 shows an example in which, at the present time (before charge and discharge), the remaining number of cycles (remaining life), which is the number of charge and discharge cycles until the SOH reaches a value that is considered the life, is C2. The graph also shows an example in which a predetermined decrease in SOH occurs between the present time (before charge and discharge) and after charge and discharge, shortening the remaining number of cycles by C1. Therefore, when the cost derivation unit 13 derives the cost using the number of charge and discharge cycles, it takes into account that the SOH of the storage battery 4 decreases due to charge and discharge cycles corresponding to the charge and discharge conditions, and that this decrease in SOH shortens the remaining number of cycles C2 (or the total number of remaining cycles Ca). Specifically, the cost derivation unit 13 multiplies the operating cost of the storage battery 4 by the ratio of the decrease in the number of remaining cycles (an example of the remaining life) corresponding to the decrease in SOH that occurs when the storage battery 4 is charged and discharged under specified charge and discharge conditions to the number of remaining cycles (an example of the remaining life), to derive the unit cost.

[0042] For example, the cost derivation unit 13 can derive the unit cost per charge / discharge cycle using the number of cycles lost due to a decrease in the SOH of the storage battery 4 that occurs under multiple charge / discharge conditions, the number of charge / discharge cycles available during the remaining life of the storage battery 4, and the operating cost required to operate the storage battery 4. In Fig. 5, when the total operating cost and the total remaining number of cycles Ca are used after the start of operation of the storage battery 4 (i.e., after the point at which the number of charge / discharge cycles shown on the horizontal axis is 0), the cost derivation unit 13 can derive the unit cost per charge / discharge cycle by calculating "unit cost = total operating cost × number of cycles lost due to charge / discharge C1 / total remaining number of cycles Ca." Alternatively, when the cost derivation unit 13 uses the operating cost from the current point in time (before charge / discharge) and the remaining number of cycles C2 from the current point in time, the cost derivation unit 13 can derive the unit cost per charge / discharge cycle by calculating "unit cost = operating cost from the current point in time × number of cycles lost due to charge / discharge C1 / remaining number of cycles C2 from the current point in time."

[0043] FIG. 6 is a graph showing an example of an SOH change curve when the storage battery 4 is charged and discharged, and a cost deriving method using the area of ​​the decreased SOH amount will be described using this graph. When the cost deriving unit 13 derives the cost using the area of ​​the decreased SOH amount, it takes into account that the SOH of the storage battery 4 decreases from the present time (before charging and discharging) to after charging and discharging due to a charge and discharge cycle corresponding to the charge and discharge conditions. Specifically, the cost deriving unit 13 multiplies the operating cost of the storage battery 4 by the ratio of the area surrounded by the SOH change curve and the amount of SOH decrease that occurs when the storage battery 4 is charged and discharged under predetermined charge and discharge conditions to the entire area surrounded by the SOH change curve, to derive the unit cost.

[0044] For example, the cost derivation unit 13 can derive the unit cost per charge / discharge cycle by using the area (loss area) surrounded by the amount of decrease in SOH of the storage battery 4 that occurs due to a plurality of charge / discharge conditions (for example, the amount of decrease in SOH shown on the vertical axis in FIG. 6) and the SOH change curve, the area surrounded by the SOH change curve corresponding to the remaining life, and the operating cost required to operate the storage battery 4. In FIG. 6, when using the total operating cost from the start of operation of the storage battery 4 (i.e., from the point when the number of charge / discharge cycles shown on the horizontal axis is 0), the cost derivation unit 13 can derive the unit cost per charge / discharge cycle by calculating "unit cost = total operating cost × loss area S2 / total remaining life area (S1 + S2 + S3)". Alternatively, when the cost derivation unit 13 uses the operating cost from the present time onwards (before charging / discharging), it can derive the unit cost per charge / discharge cycle by calculating "unit cost = operating cost from the present time onwards × loss area S2 × remaining life area (S2 + S3)".

[0045] The charge / discharge condition determination unit 17 determines, as the target charge / discharge condition, the charge / discharge condition that maximizes the profit obtained by subtracting the unit cost from the unit revenue under each charge / discharge condition, among the multiple types of charge / discharge conditions. For example, referring to FIGS. 2 and 3, when the storage battery 4 is charged / discharged under charge / discharge condition A, the profit obtained by subtracting Za1 (yen / (kWh-charge / discharge cycle)), which is the unit cost per charge / discharge cycle, from Za2 (yen / (kWh-charge / discharge cycle)), which is the unit revenue per charge / discharge cycle, is [Za2-Za1] (yen / (kWh-charge / discharge cycle)). Similarly, the profit obtained when the storage battery 4 is charged / discharged under charge / discharge condition B is [Zb2-Zb1] (yen / (kWh-charge / discharge cycle)). Furthermore, the profit obtained when the storage battery 4 is charged / discharged under charge / discharge condition C is [Zc2-Zc1] (yen / (kWh-charge / discharge cycle)). Then, the charge / discharge condition determination unit 17 determines the charge / discharge condition that maximizes the profit as the target charge / discharge condition. The charge / discharge condition determination unit 17 determines the target charge / discharge condition for the storage battery 4 of each facility 2 using the above procedure and stores it in the information storage unit 16. In other words, the information storage unit 16 stores the target charge / discharge condition determined for each storage battery 4.

[0046] Then, the charge / discharge condition output unit 18 outputs the determined target charge / discharge conditions to the storage battery 4 via the information and communication network 5, causing the storage battery 4 to charge / discharge in accordance with the target charge / discharge conditions. For example, when the charge / discharge condition output unit 18 acquires information about a purchase bid for an electricity product from the market information providing device 6, it determines charge / discharge conditions for the storage battery 4 according to the electricity product, and instructs the storage battery 4, which has the charge / discharge conditions as its target charge / discharge conditions, to charge / discharge in accordance with the target charge / discharge conditions.

[0047] By determining the target charge / discharge conditions of the storage battery 4 in the manner described above, the storage battery management system 10 can prevent the life of the storage battery 4 from being shortened as much as possible while making it possible to obtain a large compensation.

[0048] <Another embodiment> In the above embodiment, the configuration of the battery management system 10 has been described using specific examples, but these have been described for illustrative purposes only, and the configuration can be changed as appropriate.

[0049] In the above embodiment, the operation of the battery management system 10 is described using several numerical examples, but these numerical values ​​are given for illustrative purposes and can be changed as appropriate.

[0050] In the above embodiment, an example was described in which, among multiple types of charging and discharging conditions, the longer the remaining life of the charging and discharging conditions, the smaller the unit income per specified unit, but the relationship between the charging and discharging conditions and the unit income is not limited to such an example.

[0051] In the above-mentioned battery management system 10, the life estimation unit 12 estimates the remaining life as the number of remaining cycles, which is the number of charge / discharge cycles that will occur in the battery 4 until it reaches its end of life when the battery 4 is charged / discharged under each of multiple types of charge / discharge conditions, the income derivation unit 15 derives the unit income per predetermined number of charge / discharge cycles that will be obtained when the battery 4 is charged / discharged under each of multiple types of charge / discharge conditions, and the cost derivation unit 13 may derive the unit cost per predetermined number of charge / discharge cycles that will be obtained by dividing the operating cost by the remaining number of cycles when the battery 4 is charged / discharged under each of multiple types of charge / discharge conditions until it reaches its end of life.

[0052] In the above-mentioned battery management system 10, the life estimation unit 12 estimates the remaining usage time as the remaining life, which is the usage time that the battery 4 will have until it reaches its end of life when the battery 4 is charged and discharged under each of multiple types of charge and discharge conditions, the income derivation unit 15 derives the unit income per specified usage time that will be obtained when the battery 4 is charged and discharged under each of multiple types of charge and discharge conditions, and the cost derivation unit 13 may derive the unit cost per specified usage time that will be obtained by dividing the operating cost by the remaining usage time when the battery 4 is charged and discharged under each of multiple types of charge and discharge conditions until it reaches its end of life.

[0053] In the above-described battery management system 10, the life estimation unit 12 estimates the remaining battery capacity, which is the battery capacity that will be generated in the battery 4 until it reaches the end of its life when the battery 4 is charged and discharged under each of a plurality of types of charge and discharge conditions, as the remaining life, the income derivation unit 15 derives the unit income per specified battery capacity that will be obtained when the battery 4 is charged and discharged under each of a plurality of types of charge and discharge conditions, and the cost derivation unit 13 may derive the unit cost per specified battery capacity that will be obtained by dividing the operating cost by the remaining battery capacity when the battery 4 is charged and discharged under each of a plurality of types of charge and discharge conditions until it reaches its end of its life.

[0054] The configurations disclosed in the above embodiments (including other embodiments, the same applies below) can be applied in combination with configurations disclosed in other embodiments, as long as no contradictions arise. Furthermore, the embodiments disclosed in this specification are examples, and the embodiments of the present invention are not limited to these and can be modified as appropriate within the scope that does not deviate from the purpose of the present invention. [Industrial Applicability]

[0055] INDUSTRIAL APPLICABILITY The present invention can be used in a storage battery management system that allows a large amount of compensation to be obtained while taking into consideration the remaining life of the storage battery. [Explanation of symbols]

[0056] 1: Power system 2: Facilities 3: Power load 4: Storage battery 5: Information and communication network 6: Market information providing device 10: Battery management system 11:Storage battery information acquisition section 12: Life estimation section 13: Cost derivation part 14: Market information acquisition department 15: Revenue derivation section 16: Information storage section 17: Charge / discharge condition determination unit 18: Charge / discharge condition output section

Claims

1. A battery management system that manages a battery that can be connected to a power grid, a battery information acquisition unit that acquires battery information indicating a state of the battery; a lifespan estimation unit that estimates a remaining lifespan of the storage battery until the end of the lifespan that will be generated in the storage battery when the storage battery is charged and discharged under each of a plurality of types of charge and discharge conditions, based on the storage battery information acquired by the storage battery information acquisition unit; an income deriving unit that derives a unit income per predetermined unit that is obtained when the storage battery is charged and discharged under each of the plurality of types of charge and discharge conditions in order to contribute to the supply and demand of electricity in the power grid; a cost derivation unit that derives a unit cost per predetermined unit when the storage battery is charged and discharged under each of the plurality of types of charge and discharge conditions during the remaining life of the storage battery, based on an operating cost required for operating the storage battery; and a charge / discharge condition determination unit that determines, from among the plurality of types of charge / discharge conditions, the charge / discharge condition that maximizes the profit obtained by subtracting the unit cost from the unit income under each charge / discharge condition as a target charge / discharge condition.

2. 2. The battery management system according to claim 1, wherein the life estimation unit estimates the remaining life under each of the plurality of charge and discharge conditions as the time when the storage battery will reach the end of its life, based on the time when the storage battery will deteriorate and its capacity maintenance rate will fall to a predetermined threshold when the storage battery is charged or discharged.

3. 2. The battery management system of claim 1, wherein the life estimation unit estimates the remaining life under each of the plurality of charging and discharging conditions by referring to the results of a durability test that measures the state of the storage battery when the storage battery is charged, discharged, and left unused.

4. The battery management system according to claim 1 , wherein the life estimation unit estimates the remaining life under each of the plurality of types of charge and discharge conditions using a remaining life estimation model based on the results of machine learning.

5. The battery management system according to claim 1 , wherein the life estimation unit estimates the remaining life under each of the plurality of types of charge and discharge conditions using a remaining life estimation model based on a root rule.

6. The battery management system according to claim 1 , wherein the cost deriving unit derives the unit cost by dividing the operating cost by the remaining life.

7. 2. The battery management system according to claim 1, wherein the cost derivation unit derives the unit cost by multiplying the operating cost by a ratio of a decrease in the remaining life corresponding to a decrease in the capacity maintenance rate that occurs when the storage battery is charged and discharged under predetermined charge and discharge conditions to the remaining life.

8. 2. The battery management system according to claim 1, wherein the cost derivation unit derives the unit cost by multiplying the operating cost by a ratio of an area surrounded by a change curve of the capacity maintenance rate and an amount of decrease in the capacity maintenance rate that occurs when the storage battery is charged and discharged under predetermined charge and discharge conditions to an entire area surrounded by the change curve of the capacity maintenance rate of the storage battery.

9. The battery management system according to any one of claims 1 to 8, further comprising a charge / discharge condition output unit that outputs the target charge / discharge conditions to the storage battery and causes the storage battery to perform charging / discharging in accordance with the target charge / discharge conditions.

10. The battery management system according to any one of claims 1 to 8, wherein the unit income is set to be smaller for a charge / discharge condition that results in a longer remaining life among the plurality of types of charge / discharge conditions.

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