Power storage device, charging method, and program

Abstract

The present invention provides a power storage device, a charging method, and a program that enable sufficient charging even in a low-temperature state. This power storage device (1) comprises a power storage module (3) in which a plurality of cells (C1 to CM) are connected, a temperature acquisition unit (220) that acquires the temperature of the power storage module (3), an SOC calculation unit (221) that calculates the state of charge (SOC, charge rate) of the power storage module (3), and a charging control unit (222) that charges the power storage module (3) at a current value set on the basis of the acquired temperature and the calculated SOC.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Japanese Patent Application No. 2020-179847 (filed October 27, 2020), the entire disclosure of which is incorporated herein by reference. [Technical Field]

[0002] The present disclosure relates to a power storage device, a charging method, and a program. [Background technology]

[0003] A system is known in which a distributed power source, such as a power storage device, is connected to a grid. The power storage device in such a system is sometimes installed outdoors in a house and used as an emergency power source in the event of a disaster.

[0004] It is known that secondary batteries included in power storage devices are prone to deterioration at high and low temperatures. For example, Patent Document 1 discloses a technology for extending the life of a battery by reducing the current value if the external temperature is lower than a predetermined temperature when the sign of the calculated second-order differential value of the charging current changes from positive to negative. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2017 / 013823 Summary of the Invention

[0006] The power storage device according to one embodiment includes: a storage module having a plurality of batteries connected thereto; a temperature acquisition unit that acquires the temperature of the power storage module; an SOC calculation unit that calculates an SOC of the power storage module; and a charge control unit that charges the power storage module with a current value that is set based on the acquired temperature and the calculated SOC.

[0007] A charging method according to one embodiment includes: A method for charging a storage module to which a plurality of batteries are connected, comprising: acquiring a temperature of the power storage module; Calculating a SOC of the storage module; Charging the power storage module with a current value that is set based on the acquired temperature and the calculated SOC.

[0008] A program according to an embodiment includes: A program used to charge a storage module having a plurality of batteries connected thereto, On the computer, acquiring a temperature of the power storage module; Calculating a SOC of the storage module; Charging the power storage module with a current value that is set based on the acquired temperature and the calculated SOC. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an example of the configuration of a power storage system including a power storage device according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating the charging state of a battery according to a charging method according to an embodiment. [Figure 3] FIG. 3 is a diagram illustrating a current value setting table used in a charging method according to an embodiment. [Figure 4] FIG. 4 is a flowchart illustrating a charging method according to one embodiment. [Figure 5] FIG. 5 is a diagram showing an example of the result of charging a battery using a charging method according to an embodiment. [Figure 6] FIG. 6 is a diagram showing another example of the results of charging a battery using a charging method according to an embodiment. [Figure 7] FIG. 7 is a diagram illustrating the charging state of a battery according to a conventional charging method. [Figure 8]FIG. 8 is a diagram illustrating a current value setting table used in a conventional charging method. [Figure 9] FIG. 9 is a diagram showing an example of the configuration of a power storage system including a power storage device according to another embodiment. [Figure 10] FIG. 10 is a diagram for explaining coefficients used in the power storage device of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] (Configuration of the energy storage system) 1 is a diagram illustrating a configuration example of a power storage system 100 including a power storage device 1 according to an embodiment of the present disclosure. The power storage system 100 is connected to a power grid 60 and supplies power to a load 70 connected to the power grid 60. The load 70 may include any electrical appliance that consumes power, such as a light, an air conditioner, or an information processing device. The power storage system 100 stores power supplied from the power grid 60 in the power storage device 1.

[0011] The power storage system 100 includes a power control device 10 and a power storage device 1. The number of power storage devices 1 included in the power storage system 100 is not limited. In the example of FIG. 1 , the power storage system 100 includes one power storage device 1, but the number may be multiple. The multiple power storage devices 1 may be connected in parallel to the power control device 10. The power storage device 1 is connected to a power grid 60 and a load 70 via the power control device 10.

[0012] The power control device 10 is also called a PCS (power conditioning system). The power control device 10 may also be called a power conditioner. The power control device 10 comprehensively controls the operation of the power storage system 100 to realize various functions. The power control device 10 controls the input and output of power between, for example, the power storage device 1, the power grid 60, and the load 70. The power control device 10 converts DC power supplied from, for example, the power storage device 1 into AC power and outputs it to the power grid 60 or the load 70.

[0013] The power storage device 1 stores power supplied from the power grid 60. The power storage device 1 supplies the stored power to a load 70. The power storage device 1 may also supply sellable power to the power grid 60. The power storage device 1 may be installed, for example, outdoors a house and used as an emergency power source in the event of a disaster. The power storage device 1 may also be used in cold regions.

[0014] (Configuration of the power storage device) The energy storage device 1 according to this embodiment includes a management module 2, an energy storage module 3, and a temperature sensor 4. The management module 2 includes a storage 21 and a controller 22. The controller 22 includes a temperature acquisition unit 220, an SOC calculation unit 221, and a charge control unit 222. FIG. 1 is an example. The energy storage device 1 does not need to include all of the components shown in FIG. 1. Furthermore, the energy storage device 1 may include components other than those shown in FIG. 1.

[0015] The storage module 3 is made up of a plurality of batteries C1 to C2 connected in series. M M is an integer of 2 or more. As an example, M is 48. In this embodiment, a plurality of batteries C1 to C M are secondary batteries having the same configuration. M When any one of the following is indicated, battery C N The power storage module 3 may also be referred to as a battery.

[0016] The management module 2 manages the power storage module 3. In particular, the management module 2 monitors the SOC (state of charge) of the power storage module 3 and controls charging and discharging.

[0017] The storage 21 serves as a storage unit and stores programs and data. The storage 21 may temporarily store processing results of the controller 22. The storage 21 may include any storage device, such as a semiconductor storage device, an optical storage device, or a magnetic storage device. The semiconductor storage device may include, for example, a semiconductor memory. The storage 21 may include multiple types of storage devices. The storage 21 may include a combination of a portable storage medium, such as a memory card, and a storage medium reader.

[0018] In this embodiment, the data stored in the storage 21 includes a current value setting table. The current value setting table will be described in detail later.

[0019] The controller 22 is, for example, a processor such as a CPU (central processing unit). The controller 22 may be an integrated circuit such as a system-on-chip in which other components are integrated. The controller 22 may be configured by combining a plurality of integrated circuits. The controller 22 comprehensively controls the operation of the power storage device 1 to realize various functions.

[0020] The temperature acquisition unit 220 acquires the temperature of the power storage module 3 detected by the temperature sensor 4. The temperature acquisition unit 220 may constantly acquire the temperature of the power storage module 3, or may acquire the temperature intermittently (for example, at intervals of 1 to 600 seconds). In this embodiment, the acquired temperature is the temperature of the power storage module 3 itself, but is not limited to this. As another example, the acquired temperature may be the operating environment temperature of the power storage module 3. The operating environment temperature of the power storage module 3 may be the temperature inside the power storage device around the power storage module 3, or may be the air temperature of the location where the power storage device 1 is installed.

[0021] The SOC calculation unit 221 calculates the SOC of the power storage module 3. A known method can be used to calculate the SOC. For example, the SOC calculation unit 221 measures and integrates the current flowing through the battery to obtain the SOC. The SOC calculation unit 221 also obtains the voltage of the power storage module 3 and calculates the SOC of the battery C.N The OCV (Open Circuit Voltage) can be calculated using the internal resistance of the battery, and the SOC can be calculated from the OCV and the SOC-OCV curve.

[0022] The charging control unit 222 controls the charging of the power storage module 3. The charging control unit 222 charges the power storage module 3 at a current value set based on the temperature acquired by the temperature acquisition unit 220 and the SOC calculated by the SOC calculation unit 221. Furthermore, the charging control unit 222 terminates the charging of the power storage module 3 when a charging completion condition, which will be described later, is satisfied. In this embodiment, the charging control unit 222 sets the current value using a current value setting table acquired from the storage 21. The charging method executed by the charging control unit 222 will be described in detail later. Here, the charging control unit 222 may determine the timing to start charging the power storage module 3 based on the state of the SOC of the power storage module 3 or a command from the power control device 10.

[0023] The temperature sensor 4 detects the temperature of the power storage module 3. In this embodiment, the temperature sensor 4 is disposed in contact with or near the power storage module 3, and detects the temperature of the power storage module 3 itself. Here, the location of the temperature sensor 4 may differ depending on the temperature of the power storage module 3 that the controller 22 uses to set the current value. For example, when the air temperature at the location where the power storage device 1 is installed is used in the calculation to set the current value, the temperature sensor 4 may be disposed outside the power storage device 1 or in a position where it takes in outside air.

[0024] (Charging method) As described above, the charging control section 222 of the power storage device 1 charges the power storage module 3 with a current value set based on the temperature and SOC. However, the conventional charging method has the following problems.

[0025] Figure 7 shows the charging status of battery C N1 is a diagram illustrating an example of the charging state of a battery. A first conventional charging method (hereinafter referred to as "first conventional method") charges a battery at low temperatures using the same current value as at room temperature. Here, room temperature is, for example, 10°C or higher. A low temperature is, for example, below 10°C. The lower limit of the low temperature is, for example, -20°C, but it may be another temperature, or the lower limit may not be set.

[0026] Characteristic curve C in Figure 7 a is the first conventional method for charging battery C at low temperature. N The voltage and SOC state when charging are shown below. Here, the end-of-charge voltage V m is battery C N is the voltage when fully charged. Battery C N When charging, the detected voltage is the end-of-charging voltage V m If this state continues for a certain period of time (for example, 60 minutes), charging is determined to be complete. m is battery C N The upper limit voltage V is determined by max The characteristic curve C may be determined by subtracting the measurement error dV (for example, 0.02 V) from the reference voltage (for example, 3.57 V). a As shown in Fig. 7, when charging at low temperatures using the first conventional method, the SOC at the end of charging does not reach the target of 90% or more, but remains at around 70%. This is because the low temperature increases the internal resistance of the battery, which increases the overvoltage d0, resulting in the battery being judged as being completed when the charge amount is insufficient. Here, the characteristic curve C in Fig. 7 ocv indicates the theoretical open circuit voltage and SOC state.

[0027] The second conventional charging method (hereinafter referred to as the "second conventional method") charges the battery using a current value smaller than that at room temperature at low temperatures. FIG. 8 is a diagram illustrating a current value setting table used in the second conventional method. The current value setting table is a table that defines the relationship between temperature, SOC, and the current value. In FIG. 8, t0, t1, t2, t3, t4, t5, and t6 are, for example, -20°C, -10°C, -5°C, 0°C, 5°C, 10°C, and 15°C, respectively. In the second conventional method, the current value used for charging is determined by which of a plurality of categories the temperature (t) of the battery falls into. The current values I 01 ~I 45 at low temperatures are smaller than the current value I 56 at room temperature (t5 ≤ t < t6). Also, for the current values I 01 ~I 56 , I 01 < I 12 < I 23 < I 34 < I 45 < I 56 holds true.

[0028] Characteristic curve C in FIG. 7 b shows the voltage and SOC states when the battery C N is charged by the second conventional method at low temperatures. In the second conventional method, when the internal resistance of the battery increases due to low temperature, the overvoltage d1 is suppressed by setting the current value smaller than the current value at room temperature. That is, in the second conventional method, the current value is made smaller so that the voltage does not reach the end-of-charge voltage V m until the SOC reaches 90% or more of the target. As shown in characteristic curve C b , in charging by the second conventional method, the SOC at the end of charging can be made 90% or more of the target at low temperatures. However, since the current value during charging is always kept small, there is a problem that the charging time becomes long.

[0029] To address these problems with conventional charging methods, the charge control unit 222 of the power storage device 1 according to this embodiment changes the current value during charging based on the temperature and SOC to charge the power storage module 3. N 2 and 3 are diagrams illustrating examples of charging states. Also, Fig. 3 is a diagram illustrating a current value setting table used in the charging method according to this embodiment. In Figs. 2 and 3, the same reference numerals are used for the same elements as in Figs. 7 and 8, and therefore description thereof will be omitted.

[0030] Characteristic curve C in Figure 2 p is charged by the charging method according to this embodiment. N 1 shows the voltage and SOC states when charging. The charging method according to this embodiment shortens the time until charging is completed by using a current value larger than that of the second conventional method, and changes the current value so that it decreases as the SOC of the storage module 3 increases, making it possible to achieve a target SOC of 90% or more at the time of charging completion.

[0031] As shown in FIG. 3, in this embodiment, the current value setting table divides not only temperature but also SOC into multiple categories, and the current value is determined according to the combination of temperature and SOC categories. The SOC may be divided into approximately the same numerical range, but is not limited to this. In this embodiment, the SOC is divided into ranges of 11% or 12%. For example, the SOC width ds in FIG. 2 may be 11%. Furthermore, the temperature may be divided into approximately the same numerical range, but is not limited to this. In this embodiment, the temperature is divided into ranges of 1°C.

[0032] When charging the power storage module 3, the charge control unit 222 classifies the SOC calculated by the SOC calculation unit 221 into one of a plurality of categories, and sets a current value according to the category. Here, when the category of the temperature acquired by the temperature acquisition unit 220 is the same and there is a second category with a higher SOC than the first category, the charge control unit 222 sets the second current value corresponding to the second category to be equal to or less than the first current value corresponding to the first category. Explaining this with reference to FIG. 3, for example, when the temperature category is t1, the second current I corresponding to the second SOC category "55%≦SOC<66%" is set to 1d is the first current I corresponding to the first SOC division "44%≦SOC<55%" 1c For example, when the temperature range is t3, the second current I corresponding to the second SOC range "66%≦SOC<77%" is 3e is the first current I corresponding to the first SOC division "44%≦SOC<55%" 3c In the example of Figure 3, j is a parameter that indicates an integer between 0 and 6, and the current value I ja , I jb , I jc , I jd and I je About I ja ≧I jb ≧I jc ≧I jd ≧I je However, this inequality does not include the case where the current values ​​corresponding to all SOC categories are the same (corresponding to the second conventional method).

[0033] Furthermore, the charge control unit 222 classifies the temperature acquired by the temperature acquisition unit 220 into one of a plurality of categories, and sets a current value according to the classified category. For example, if the temperature rises or falls during charging of the power storage module 3 and changes the temperature category, a current value according to the temperature category after the change is set. Here, when the calculated SOC category is the same and there is a third category for temperature and a fourth category with a lower temperature, the charge control unit 222 sets the fourth current value corresponding to the fourth category to be equal to or lower than the third current value corresponding to the third category. Explaining this with reference to FIG. 3, for example, when the SOC category is "11%≦SOC<22%, " the second current I corresponding to the fourth temperature category "t1" is set to 1b is the first current I corresponding to the third temperature interval "t2" 2b For example, when the SOC range is "44%≦SOC<55%, the second current I corresponding to the fourth temperature range "t3" is 3c is the first current corresponding to the third temperature segment "t5" 5c In the example of Figure 3, x is a parameter that indicates one of {a, b, c, d, e}, and the current value I 0x , I 1x , I 2x , I 3x , I 4x , I 5x and I 6x About I 0x ≦I 1x ≦I 2x ≦I 3x ≦I 4x ≦I 5x ≦I 6x However, this inequality does not require that the current values ​​corresponding to all temperature ranges be the same.

[0034] The charging control unit 222 acquires the SOC and temperature of the power storage module 3, determines the current value based on a combination of these and the current value setting table, and charges the power storage module 3. As shown in FIG. 2, the characteristic curve C phas a wave-like portion where the voltage temporarily drops when the SOC reaches a specific value as the SOC of the power storage module 3 increases. The specific SOC value at which the voltage drops corresponds to the boundary between SOC categories. In the example of FIG. 3, the specific values ​​are, for example, 44%, 55%, 66%, etc. When the SOC rises during charging and the category changes, the charge control unit 222 sets a lower current value. At this time, the voltage of the power storage module 3 drops. Thereafter, the voltage of the power storage module 3 gradually increases due to changes in internal resistance caused by a rise in the temperature inside the power storage module 3, etc. Therefore, the characteristic curve C p has a wavy portion.

[0035] Here, as mentioned above, battery C N When charging, the detected voltage is the end-of-charging voltage V m When this state continues for a certain period of time, it is determined that charging is complete. In order to shorten the time until charging is complete, the charging method according to this embodiment uses a current value larger than that of the second conventional method. Therefore, by the time the SOC reaches the target 90% or more, the voltage will reach the end-of-charge voltage V m However, in the charging method according to the present embodiment, the voltage drops when the SOC reaches a certain value. Therefore, the voltage temporarily drops to the end-of-charge voltage V before the charging is completed. m Even if the voltage temporarily drops to the end-of-charge voltage V, this state will not continue long enough to determine that charging is complete. Therefore, the charging method according to this embodiment can achieve a SOC of 90% or more at the end of charging. m To prevent this state from continuing, i.e., to effectively prevent erroneous determination of the completion of charging, it is preferable to set many boundaries of SOC categories (specific SOC values ​​at which the voltage drops) associated with the current value. The SOC is preferably categorized in a range of at least 15% or less. For example, the SOC may be categorized in a range of 11% or 12%, as in this embodiment. The SOC may also be categorized in an even narrower range (e.g., a range of 8%).

[0036] (Electricity storage method) 4 is a flowchart illustrating a charging method according to this embodiment. The controller 22 of the power storage device 1 charges the power storage module 3 in accordance with the flowchart shown in FIG.

[0037] The charging control unit 222 of the controller 22 acquires the current value setting table from the storage 21 (step S1).

[0038] The temperature acquisition unit 220 of the controller 22 acquires the temperature of the power storage module 3 from the temperature sensor 4 (step S2).

[0039] The SOC calculation unit 221 of the controller 22 receives information required for calculation from the power storage module 3 (for example, the battery C N The measured voltage and current values ​​are acquired, and the SOC of the power storage module 3 is calculated (step S3).

[0040] The charge control unit 222 of the controller 22 sets a current value used to charge the power storage module 3 based on the temperature acquired by the temperature acquisition unit 220 and the SOC calculated by the SOC calculation unit 221 (step S4). At this time, the charge control unit 222 uses the current value setting table. The charge control unit 222 charges the power storage module 3 at the set current value.

[0041] When the charging completion condition is satisfied (Yes in step S5), the charging control section 222 of the controller 22 ends the charging process. N The measured voltage is the end-of-charge voltage V m The charging control unit 222 may determine whether the battery C is in a low state or not for a certain period of time (for example, 60 minutes). N A voltage measurement may be received and used to determine end of charge.

[0042] If the charge completion condition is not satisfied (No in step S5), the controller 22 returns to the processing in step S2.

[0043] (Example) The above-described charging method was carried out in the energy storage device 1 according to this embodiment, and the energy storage module 3 was charged at a low temperature. N 5 is referred to as a first embodiment, and the embodiment whose results are shown in FIG. 6 is referred to as a second embodiment.

[0044] In the first example, the temperature of the power storage module 3 was -10°C, and the SOC of the power storage module 3 before charging, i.e., the SOC in the initial state, was 10%. In Fig. 5, CC indicates the measured value of the current of the power storage module 3. CV max is battery C N The CV indicates the maximum voltage at the end of charging. min is battery C N The CV indicates the voltage measurement value of the battery that showed the minimum voltage at the end of charging. avg All batteries C N In the first example, the SOC at the end of charging was 94.2%, which was above the target of 90%. Here, as shown by P in Figure 5, when the SOC was 19%, some batteries C N The voltage at the end of charging is V m The voltage reaches the end of charging voltage V m After this state continued for 5 minutes, the SOC reached 22% and the voltage dropped. Here, the charge completion condition is when the voltage reaches the end-of-charge voltage V m The condition where the battery voltage reaches 100% or more continues for 60 minutes or more. Therefore, there was no erroneous determination of the completion of charging in the first embodiment. Furthermore, the charging time was reduced to less than half that of the second conventional method.

[0045] In the second example, the temperature of the storage module 3 was -15°C. Other conditions were the same as those in the first example. In the second example, the SOC at the end of charging was 98.4%, which was above the target of 90%. Here, as shown in FIG. 6, several batteries C N The voltage at the end of charging is V mHowever, the duration of this was within one minute. Therefore, there was no erroneous determination of the completion of charging in the second example. Furthermore, the charging time was reduced to less than one-third of that in the second conventional method.

[0046] As is clear from the results of the examples, the energy storage device 1 and charging method according to this embodiment enable sufficient charging even at low temperatures due to the above-mentioned configuration and steps. Furthermore, the energy storage device 1 and charging method according to this embodiment can significantly reduce the charging time at low temperatures compared to conventional charging methods that charge batteries using a current value smaller than that at room temperature.

[0047] Although the embodiments have been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications and alterations based on the present disclosure. Therefore, it should be noted that these modifications and alterations are included in the scope of the present disclosure. For example, the functions included in each component, each means, each step, etc. can be rearranged so as not to be logically inconsistent, and multiple means and / or steps can be combined or divided into one.

[0048] In the above embodiment, the charge control unit 222 sets the current value according to the classification, and sets the current value to be smaller as the SOC increases even at room temperature. Here, the high internal resistance of the power storage module 3 becomes a problem especially at low temperatures. Therefore, when the acquired temperature is greater than a predetermined threshold (for example, 10°C), the charge control unit 222 may set the current value to a predetermined value that does not depend on the SOC. For example, t5 (10°C) and t6 (15°C) in FIG. 3 are room temperatures. I in FIG. 5a , I 5b , I 5c , I 5d and I 5e may have the same value I5. Also, I in FIG. 6a , I 6b , I 6c , I 6d , I 6e Furthermore, the values ​​I5 and I6 may be the same.

[0049] Although the embodiments have been described mainly in terms of an apparatus and a method, the embodiments of the present disclosure may also be realized as a program executed by a processor included in the apparatus, or as a storage medium on which a program is recorded, and it should be understood that these are also encompassed within the scope of the present disclosure.

[0050] For example, the management module 2 may be implemented as a computer including a storage device such as a memory and a hard disk drive, and a control device such as a CPU (central processing unit) and other processors. In this case, the storage 21 may be implemented as a storage device of the computer. Also, the controller 22 may be implemented as a control device of the computer. The program may be stored in the storage device and read from the control device when executed.

[0051] The programs stored in the storage 21 may include those that cause the controller 22 to function as the temperature acquisition unit 220, the SOC calculation unit 221, and the charge control unit 222. Furthermore, the controller 22 may realize various functions by executing instructions included in the programs stored in the storage 21. The controller 22 may realize the functions of the temperature acquisition unit 220, the SOC calculation unit 221, and the charge control unit 222 by executing instructions of the programs read from the storage 21.

[0052] Furthermore, in the above embodiment, the charge control unit 222 charges the power storage module 3 at a current value that is set based on the temperature and SOC. Here, the set current value may be set based on a state quantity of the power storage module 3 that is different from the temperature and SOC. For example, in another embodiment, the controller 22 may use a current value that takes into account the SOH (States of Health, or degree of deterioration) of the power storage module 3. That is, the charge control unit 222 may charge the power storage module 3 at a current value that is set based on the acquired temperature, the calculated SOC, and the calculated SOH. Here, the SOH indicates the deterioration state of the power storage module 3 and is calculated as the ratio of the current full charge capacity to the initial full charge capacity (or rated capacity). Here, another embodiment will be described in detail below.

[0053] Fig. 9 is a diagram showing an example of the configuration of a power storage system 100 including a power storage device 1 according to another embodiment. This differs from the above embodiment (see Fig. 1) in that the controller 22 further includes an SOH calculation unit 223. Furthermore, the charge control unit 222 adjusts the current value using the SOH. Elements other than these are the same as those in Fig. 1, and therefore description thereof will be omitted.

[0054] The SOH calculation unit 223 calculates the SOH of the power storage module 3. A known method can be used to calculate the SOH. For example, the SOH calculation unit 223 may acquire information about the usage environment, including temperature, and calculate the SOH of the power storage module 3 using a mathematical model of deterioration that uses the information about the usage environment as a parameter. Alternatively, for example, the SOH calculation unit 223 may acquire the amount of discharge from the power storage module 3 from a fully charged state to a completely discharged state, and calculate the ratio to the rated capacity to calculate the SOH.

[0055] The charging control unit 222 sets the current value using the current value setting table acquired from the storage 21 as described above, and the set current value (hereinafter referred to as the pre-adjustment current value) is adjusted based on the SOH value (hereinafter referred to as Q SOHIn another embodiment, the adjusted current value is used to charge the power storage module 3. If the current value before adjustment is I, then the adjusted current value I adj I adj =I×(Q SOH × α).

[0056] However, (Q SOH ×α) exceeds 1, (Q SOH ×α) is set to 1. In other words, (Q SOH × α) exceeds 1, I adj =I.

[0057] Here, when the energy storage module 3 deteriorates over time, the internal resistance of the battery becomes higher than at the initial stage (at the time of manufacture), and the overvoltage increases, which may result in the determination that charging is complete at a smaller charge amount than at the initial stage. Therefore, it is preferable to adjust the energy storage module 3 that has deteriorated over time so that charging is performed at an even smaller current value than in the above embodiment, particularly at low temperatures. The degree of deterioration of the energy storage module 3 over time can be known from the SOH. In the energy storage device 1 according to another embodiment, the adjusted current value I adj By charging at this temperature, it becomes possible to sufficiently charge the power storage module 3, which has deteriorated over time, even in a low temperature state.

[0058] Here, Q SOH is a value less than 1. For example, if storage module 3 is not very deteriorated and the SOH is 90%, Q SOH For example, if the deterioration of storage module 3 is progressing and the SOH is 40%, Q SOH is 0.4. The coefficient α is introduced to prevent the current value after adjustment from becoming excessively small (i.e., the charging time from becoming long), particularly when the deterioration of the power storage module 3 is progressing. The coefficient α is a value greater than 1.

[0059] FIG. 10 is a diagram for explaining the coefficient α. The coefficient α is set according to the temperature (t) of the battery. In the example of FIG. 10, the threshold temperatures T1 to T 10 About T1 <T2<T3<T4<T5<T6<T7<T8<T9<T 10 Also, the coefficient α is α0 to α 10 For, 1<α0<α1<α2<α3<α4<α5<α6<α7<α8<α9<α 10 As an example, T1 may be 15°C. In this example, when the battery temperature (t) is less than 15°C, the coefficient α is set to α0. α0 may be 1.1 as a specific example. For example, Q SOH If Q is 0.9, SOH × α) is 0.99. Also, the deterioration of the storage module 3 is progressing and Q SOH If is 0.4, then (Q SOH × α) is 0.44. At this time, the adjusted current value (I adj ) is set to be smaller than half of the current value according to the current value setting table. By adjusting the current value according to the SOH in this way, it becomes possible to sufficiently charge even a storage module 3 that has deteriorated over time, even in a low-temperature state.

[0060] Also, as an example, T 10 In this example, when the battery temperature (t) is 24°C or higher, the coefficient α is α 10 is set to α 10 For example, Q can be 2.0. SOH If is greater than 0.5, then (Q SOH ×α) exceeds 1, so (Q SOH × α) = 1. That is, the adjusted current value is equal to the pre-adjustment current value. At high temperatures where the effect of an increase in internal resistance due to degradation of the power storage module 3 is not significant, the charging current value is set according to the current value setting table, as in the above embodiment.

[0061] In this disclosure, descriptions such as "first" and "second" are identifiers for distinguishing the configuration. In this disclosure, configurations distinguished by descriptions such as "first" and "second" may have their numbers exchanged. The exchange of identifiers is performed simultaneously. The configurations remain distinguished even after the exchange of identifiers. Identifiers may be deleted. A configuration from which an identifier has been deleted is distinguished by a symbol. The descriptions of identifiers such as "first" and "second" in this disclosure should not be used solely to interpret the order of the configurations or to justify the existence of an identifier with a smaller number.

[0062] The Sustainable Development Goals (SDGs) are 17 international goals adopted at the United Nations Summit in September 2015. An electricity storage device 1 and an electricity storage method according to an embodiment can contribute to achieving the 17 SDGs, such as goals 7. Affordable and clean energy, 9. Industry, innovation and infrastructure, and 11. Sustainable cities and communities. [Explanation of symbols]

[0063] 1. Energy storage device 2 Management Module 3 Energy storage module 4 Temperature Sensors 10 Power control device 21. Storage 22 Controller 60 Power system 70 load 100 Energy Storage System 220 Temperature acquisition section 221 SOC calculation section 222 Charging control unit 223 SOH calculation section

Claims

1. a storage module having a plurality of batteries connected thereto; a temperature acquisition unit that acquires the temperature of the power storage module; an SOC calculation unit that calculates an SOC of the power storage module; an SOH calculation unit that calculates the SOH of the storage module; a charge control unit that charges the power storage module at a current value that is set based on the acquired temperature, the calculated SOC, and the calculated SOH; The charging control unit adjusts the current value before adjustment based on the acquired temperature and the calculated SOC by multiplying the calculated SOH value by a coefficient α that is set according to the temperature, and charges the storage module with the adjusted current value.

2. The charging control unit classifying the calculated SOC into one of a plurality of categories, and setting the pre-adjustment current value according to the category; 2. The power storage device according to claim 1, wherein, when the acquired temperature range is the same and there is a second range in which the SOC is greater than a first range in the SOC, a second current value corresponding to the second range is set to be equal to or less than a first current value corresponding to the first range.

3. The charging control unit classifying the acquired temperature into one of a plurality of categories, and setting the pre-adjustment current value according to the category; 3. The storage device according to claim 1, wherein, when the calculated SOC range is the same and there is a third range for the temperature and a fourth range for the temperature that is lower than the third range, a fourth current value corresponding to the fourth range is set to be equal to or lower than the third current value corresponding to the third range.

4. 4. The power storage device according to claim 1, wherein the charge control unit sets the pre-adjustment current value to a predetermined value independent of the calculated SOC when the acquired temperature is greater than a predetermined threshold value.

5. a storage that stores a current value setting table that defines a relationship between the temperature and the SOC and the current value before adjustment; The power storage device according to claim 1 , wherein the charge control unit sets the current value using the pre-adjustment current value setting table acquired from the storage.

6. A method for charging a storage module to which a plurality of batteries are connected, comprising: acquiring a temperature of the power storage module; Calculating an SOC of the storage module; Calculating the SOH of the storage module; charging the power storage module with a current value that is set based on the acquired temperature, the calculated SOC, and the calculated SOH; Charging the storage module is a charging method in which a current value before adjustment based on the acquired temperature and the calculated SOC is adjusted by multiplying the calculated SOH value by a coefficient α that is set according to the temperature, and the storage module is charged with the adjusted current value.

7. A program used to charge a storage module having a plurality of batteries connected thereto, On the computer, acquiring a temperature of the power storage module; Calculating an SOC of the storage module; Calculating the SOH of the storage module; charging the power storage module with a current value that is set based on the acquired temperature, the calculated SOC, and the calculated SOH; Charging the storage module includes adjusting a current value before adjustment based on the acquired temperature and the calculated SOC by multiplying the calculated SOH value by a coefficient α that is set according to the temperature, and charging the storage module with the adjusted current value.

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