Power storage system and control method

Abstract

This electricity storage system comprises: two or more electricity storage devices connected to one power conditioning device in parallel; and a control unit for controlling the connection state between each of the two or more electricity storage devices and the one power conditioning device. The control unit sets a priority on charging the two or more electricity storage devices on the basis of information about the temperature of each of the two or more electricity storage devices and controls the connection state on the basis of the priority.

Description

[Technical Field]

[0001] The present disclosure relates to a power storage system and a control method. [Background technology]

[0002] Conventionally, there is known a power storage system in which two or more power storage devices are connected in parallel to one power conversion device (PCS; Power Conditioning System). In such a power storage system, a technique has been proposed for controlling a switch provided between each power storage device and a load so as to reduce a voltage difference between the two or more power storage devices (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2013 / 121849 Brochure Summary of the Invention

[0004] One aspect of the disclosure is a power storage system comprising two or more power storage devices connected in parallel to one power conversion device, and a control unit that controls the connection state between each of the two or more power storage devices and the one power conversion device, wherein the control unit sets priorities for charging the two or more power storage devices based on information regarding the temperature of each of the two or more power storage devices, and controls the connection state based on the priorities.

[0005] One aspect of the disclosure is a control method comprising: step A of setting priorities for charging two or more power storage devices connected in parallel to one power conversion device based on information regarding the temperatures of each of the two or more power storage devices; and step B of controlling the connection state between each of the two or more power storage devices and the one power conversion device based on the priorities. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a diagram showing a power storage system 100 according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating the controller 130 according to the embodiment. [Figure 3] FIG. 3 is a diagram for explaining control of the connection state according to the embodiment. [Figure 4] FIG. 4 is a diagram illustrating a control method according to the embodiment. [Figure 5] FIG. 5 is a diagram for explaining control of the connection state according to the first modification. [Figure 6] FIG. 6 is a diagram for explaining control of the connection state according to the first modification. [Figure 7] FIG. 7 is a diagram illustrating a control method according to the first modification. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, embodiments will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, the drawings are schematic.

[0008] [Embodiment] (Energy storage system) A power storage system according to an embodiment will be described below. As shown in Fig. 1, the power storage system 100 includes two or more power storage devices 110, a PCS (Power Conditioning System) 120, and a controller 130. Each of the two or more power storage devices 110 is connected in parallel to one PCS 120 by a wiring 141.

[0009] 1, a power storage device 110A and a power storage device 110B are illustrated as examples of the power storage device 110. A wiring 141A connects the power storage device 110A to the PCS 120, and a wiring 141B connects the power storage device 110A to the power storage device 110B. For the sake of simplicity, only one of the positive and negative wirings 141 is illustrated in FIG.

[0010] The power storage device 110 is a device that stores power. Specifically, the power storage device 110 may have two or more storage cells that store power. The two or more storage cells may be connected in series to form a cell string. The power storage device 110 may have two or more cell strings that are connected in parallel to each other. The power storage device 110 may have discharge resistors connected to the two or more storage cells, respectively, and may have a function (hereinafter, cell balancing function) of suppressing variations in voltage values ​​of the two or more storage cells by discharging from the storage cells to the discharge resistors. The voltage values ​​of the storage cells may be equalized by repeatedly charging or discharging the power storage device 110.

[0011] 1, the power storage device 110 has an interface terminal 111 that outputs power from the power storage device 110 or inputs power to the power storage device 110. For example, the power storage device 110A has an interface terminal 111A, and the power storage device 110B has an interface terminal 111B.

[0012] 1, the power storage device 110 has a switch 112 for switching the connection state between the power storage device 110 and the PCS 120. For example, the power storage device 110A has a switch 112A, and the power storage device 110B has a switch 112B.

[0013] 1, power storage device 110 has sensor 113 that detects the temperature of power storage device 110. For example, power storage device 110A has sensor 113A, and power storage device 110B has sensor 113B.

[0014] The PCS 120 is an example of a power conversion device. The PCS 120 converts DC power output from the power storage device 110 into AC power. The PCS 120 converts AC power into DC power that is input to the power storage device 110. The PCS 120 includes a DC / DC converter, an inverter, and the like.

[0015] The controller 130 controls the PCS 120. The controller 130 is connected to the PCS 120 wirelessly or via a wire. The controller 130 is connected to the power storage device 110 (for example, the switch 112 and the sensor 113) wirelessly or via a wire. The wireless method may be a method conforming to a standard such as IEEE802.11a / b / g / n, ZigBee, Wi-SUN, or LTE. The wired method may be a method conforming to a standard such as IEEE802.3.

[0016] (controller) The controller according to the embodiment will be described below. As shown in FIG.

[0017] The acquisition unit 131 acquires information related to the temperature of the power storage device 110. For example, the acquisition unit 131 may be connected to the sensor 113 of the power storage device 110 and acquire the temperature of the power storage device 110 detected by the sensor 113.

[0018] The control unit 132 may include at least one processor. The at least one processor may be configured by a single integrated circuit (IC), or may be configured by multiple circuits (such as integrated circuits and / or discrete circuits) that are communicatively connected.

[0019] The control unit 132 controls the PCS 120 to control the discharging operation and charging operation of the power storage device 110. In the embodiment, the control unit 132 configures a control unit that controls the connection state between each of two or more power storage devices 110 and one PCS.

[0020] Specifically, the control unit 132 sets priorities for charging the two or more power storage devices 110 based on information about the temperatures of each of the two or more power storage devices 110. The control unit 132 controls the connection state based on the priorities. The control of the connection state includes control to disconnect the power storage device 110 with a low priority from the PCS 120. The control of the connection state will be described later (see FIG. 3).

[0021] (Connection state control) The following describes the control of the connection state according to the embodiment. The following mainly describes a case where the power storage device 110A and the power storage device 110B are connected in parallel to the PCS 120. The following illustrates a case where the power storage device 110A and the power storage device 110B have the same storage capacity.

[0022] Here, the charge rate of each of power storage device 110A and power storage device 110B has the following characteristics. The charge rate may be expressed as a charge current (A) per unit time, or as a C (Coulomb) rate. In the following, a case will be described in which the charge rate is expressed as a charge current (A) per unit time.

[0023] For example, when the temperature of the power storage device 110 is higher than a first threshold (e.g., 0°C), the charge rate applicable to the power storage device 110 is a first charge rate (e.g., 10 A), and when the temperature of the power storage device 110 is equal to or lower than the first threshold (e.g., 0°C), the charge rate applicable to the power storage device 110 is a second charge rate (e.g., 1 A). The second charge rate is a charge rate lower than the first charge rate.

[0024] Under these assumptions, a state in which both power storage device 110A and power storage device 110B are connected to PCS 120 will be considered.

[0025] First, in a case where the temperatures of both power storage device 110A and power storage device 110B are higher than the first threshold (hereinafter referred to as case 1), the charge rate applicable to each of power storage device 110A and power storage device 110B is the first charge rate, so PCS 120 outputs a current that is twice the first charge rate and supplies a current equivalent to the first charge rate to each of power storage device 110A and power storage device 110B.

[0026] Here, assuming a case where charging is started when the overall SOC (State Of Charge) (hereinafter referred to as overall SOC) of the power storage system 100 (i.e., power storage device 110A and power storage device 110B) is 0%, as shown in FIG. 3, charging of each of power storage device 110A and power storage device 110B is performed at a first charging rate until the overall SOC reaches a first threshold value TH.

[0027] The first threshold TH is a first threshold for switching between CC (Constant Current) charging and CV (Constant Voltage) charging. CC charging is a charging method applied when the SOC is lower than the first threshold TH, and CV charging is a charging method applied when the SOC is equal to or higher than the first threshold TH.

[0028] Second, in a case where the current temperature of power storage device 110A is higher than the first threshold value and the current temperature of power storage device 110B is lower than the first threshold value (hereinafter referred to as case 2), the charge rate applicable to power storage device 110A is the first charge rate, but the charge rate applicable to power storage device 110B is the second charge rate. However, the charge rates of power storage device 110A and power storage device 110B cannot be controlled individually. Therefore, because the charge rate applicable to each of power storage device 110A and power storage device 110B is the second charge rate, PCS 120 outputs a current that is twice the second charge rate and supplies a current equivalent to the second charge rate to each of power storage device 110A and power storage device 110B.

[0029] Here, assuming a case where charging is started when the overall SOC is 0%, as shown in FIG. 3, the charging time for the entire power storage system 100 becomes longer than in Case 1. In this embodiment, the controller 130 focuses on the above-mentioned case 2 and performs the following operations.

[0030] First, the controller 130 may execute a first control to disconnect from the PCS 120 a first power storage device, of the two or more power storage devices 110, whose current temperature is lower than a first threshold value.

[0031] For example, similar to case 2, consider a case (hereinafter, case 3) in which the current temperature of power storage device 110A is higher than the first threshold and the current temperature of power storage device 110B is lower than the first threshold. In case 3, controller 130 executes first control to disconnect power storage device 110B, whose current temperature is lower than the first threshold, from PCS 120. According to the first control, power storage device 110B is disconnected from PCS 120, and therefore the charge rate of power storage device 110, whose temperature is higher than the first threshold, can be set to the first charge rate.

[0032] Here, assuming a case where charging is started when the overall SOC is 0%, charging of power storage device 110A is executed at the first charging rate until the storage capacity of power storage device 110A reaches a predetermined capacity (for example, 50% of the overall SOC), as shown in Fig. 3. Therefore, the charging time for power storage system 100 as a whole can be shortened compared to Case 2.

[0033] Second, when the storage capacity of a second storage device other than the first storage device among the two or more storage devices 110 reaches a predetermined capacity, the controller 130 executes a second control to disconnect the second storage device from the PCS 120 and connect the first storage device to the PCS 120.

[0034] For example, consider the above-mentioned case 3. In case 3, when the storage capacity of the power storage device 110A other than the power storage device 110B reaches a predetermined capacity, the controller 130 executes a second control to disconnect the power storage device 110A from the PCS 120 and connect the power storage device 110B to the PCS 120. The predetermined capacity may be a capacity at which the charging method of the power storage device 110A switches from CC charging to CV charging. The predetermined capacity may also be a capacity at which the SOC of the power storage device 110A is 100%.

[0035] Here, assuming a case where charging is started when the overall SOC is 0%, after the storage capacity of power storage device 110A reaches a predetermined capacity (for example, 50% of the overall SOC), charging of power storage device 110B is executed at the second charging rate, as shown in Fig. 3. Therefore, charging of power storage device 110B can also be executed appropriately.

[0036] (Control method) The control method according to the embodiment will be described below, with the operation of the controller 130 being mainly described below.

[0037] As shown in FIG. 4, in step S10, the controller 130 acquires the temperature of the power storage device 110 detected by the sensor 113 as information relating to the temperature of each of the two or more power storage devices 110.

[0038] In step S11, controller 130 determines whether a first condition is satisfied. The first condition may be a condition that a first power storage device whose current temperature is lower than a first threshold exists and a second power storage device whose temperature is higher than the first threshold exists. If the first condition is not satisfied, controller 130 returns to the process of step S10 without changing the connection state between power storage device 110 and PCS 120. If the first condition is satisfied, controller 130 executes the process of step S12.

[0039] In step S12, the controller 130 sets priorities for charging the two or more power storage devices 110 based on information relating to the temperatures of each of the two or more power storage devices 110.

[0040] In step S13, the controller 130 controls the connection state based on the priority order. Specifically, the first control and the second control described above are executed.

[0041] In the embodiment, the priority is set so that charging of the second power storage device whose current temperature is higher than the first threshold is given priority over charging of the first power storage device whose current temperature is lower than the first threshold.

[0042] (Action and effect) In the embodiment, the controller 130 sets priorities for charging the two or more power storage devices 110 based on information relating to the temperatures of each of the two or more power storage devices 110. The controller 130 controls the connection state between the power storage devices 110 and the PCS 120 based on the priorities. With this configuration, it is possible to prevent a decrease in the charge rate of the power storage system 100 as a whole, while taking into consideration the constraint imposed by the charge rate of the first power storage device whose current temperature is lower than the first threshold value.

[0043] For example, in the embodiment, the first control described above is executed, which can shorten the charging time for the entire power storage system 100. In the embodiment, the second control described above is executed, which can appropriately charge the first power storage device whose current temperature is lower than the first threshold value.

[0044] [Change Example 1] Modification 1 of the embodiment will be described below, focusing mainly on the differences from the embodiment.

[0045] In the first modification, a case will be described in which the rate of current that the PCS 120 can supply (hereinafter referred to as the supplyable rate) is smaller than the overall charging rate of two or more power storage devices 110. Such a case may be one in which the power storage system 100 is in an autonomous operation in which it is disconnected from the power grid, and the power storage system 100 is charged by a distributed power source such as a solar cell device.

[0046] The following mainly describes a case where the power storage device 110A and the power storage device 110B are connected in parallel to the PCS 120. The case where the power storage device 110A and the power storage device 110B have the same power storage capacity will be exemplified.

[0047] Here, the charge rates of the power storage device 110A and the power storage device 110B each have the following characteristics. For example, when the temperature of the power storage device 110 is higher than a first threshold (for example, 0°C), the charge rate applicable to the power storage device 110 is a first charge rate (for example, 10 A), and when the temperature of the power storage device 110 is equal to or lower than the first threshold (for example, 0°C), the charge rate applicable to the power storage device 110 is a second charge rate (for example, 1 A). The second charge rate is a charge rate lower than the first charge rate.

[0048] Furthermore, a case will be illustrated in which the available supply rate of PCS 120 (for example, 10 A) is lower than the overall charge rate (for example, 20 A) of power storage device 110A and power storage device 110B, but the available supply rate is higher than the second charge rate.

[0049] Under these assumptions, a case will be described in which the temperature of power storage device 110B is predicted to be lower than the first threshold at time T1, as shown in Figures 5 and 6. Figures 5 and 6 assume a case in which charging starts when the overall SOC is 0%. In such a case, the following options are possible as operations to be performed by controller 130.

[0050] In option 1, because the temperatures of the power storage device 10A and the power storage device 10B are higher than the first threshold value until time T1, the controller 130 charges the power storage device 10A and the power storage device 10B without disconnecting the power storage device 10A and the power storage device 10B from the PCS 120. The PCS 120 outputs a current equivalent to the available supply rate, and the power storage device 10A and the power storage device 10B are charged at a rate that is half the available supply rate (control 1A). At time T1, the controller 130 executes a first control to disconnect the power storage device 10B from the PCS 120. Therefore, the power storage device 10A is charged at the available supply rate (control 1B). When the storage capacity of power storage device 110A reaches a predetermined capacity, controller 130 executes second control to disconnect power storage device 110A from PCS 120 and connect power storage device 110B to PCS 120. Therefore, charging of power storage device 110B is executed at a second charging rate (control 1C).

[0051] Thus, option 1 is an option in line with the embodiment described above.

[0052] In option 2, the controller 130 executes a third control to disconnect the power storage device 10A other than the power storage device 10B whose future temperature is predicted to be lower than the first threshold value from the PCS 120. Therefore, charging of the power storage device 10B is executed at the available supply rate until time T1 (control 2A). At time T1, the controller 130 disconnects the power storage device 10B from the PCS 120 and connects the power storage device 110A to the PCS 120. Therefore, after time T1, charging of the power storage device 110B is executed at the available supply rate (control 2B).

[0053] In this way, in option 2, charging of power storage device 10B, whose future temperature is predicted to be lower than the first threshold, is given priority over power storage device 10A, and therefore the charging time for the entire power storage system 100 can be shortened compared to option 1.

[0054] Option 2 may be expressed as follows: The controller 130 executes third control (control 2A shown in FIG. 6 ) to disconnect from the PCS 120 a fourth power storage device other than a third power storage device whose future temperature is predicted to be lower than the first threshold based on information related to temperature, among the two or more power storage devices 110. When the power storage capacity of the third power storage device reaches a predetermined capacity or when the current temperature of the third power storage device becomes lower than the first threshold, the controller 130 executes fourth control (control 2B shown in FIG. 6 ) to disconnect the third power storage device from the PCS 120 and connect the fourth power storage device to the PCS 120.

[0055] (Control method) The following describes a control method according to Modification 1. The following mainly describes the operation of controller 130.

[0056] As shown in FIG. 7, in step S20, the controller 130 acquires the temperature of the power storage device 110 detected by the sensor 113 as information relating to the temperature of each of the two or more power storage devices 110.

[0057] In step S21, the controller 130 determines whether a second condition is satisfied. The second condition may be a condition that there is a third power storage device whose future temperature is predicted to be lower than the first threshold, and the supplyable rate of the PCS 120 is lower than the charge rate of the power storage system 100. If the predetermined condition is not satisfied, the controller 130 returns to the processing of step S20 without changing the connection state between the power storage device 110 and the PCS 220. If the predetermined condition is satisfied, the controller 130 executes the processing of step S22.

[0058] In step S22, the controller 130 sets priorities for charging the two or more power storage devices 110 based on information relating to the temperatures of each of the two or more power storage devices 110.

[0059] In step S23, the controller 130 controls the connection state based on the priority order, specifically, the third control and the fourth control described above are executed.

[0060] In the first modification, the priority order is set so that charging of the third power storage device, whose temperature is predicted to be lower than the first threshold in the future, takes precedence over charging of the fourth power storage device other than the third power storage device.

[0061] (Action and effect) In the first modification, the controller 130 sets priorities for charging the two or more power storage devices 110 based on information relating to the temperatures of each of the two or more power storage devices 110. The controller 130 controls the connection state between the power storage devices 110 and the PCS 120 based on the priorities. This configuration makes it possible to prevent a decrease in the charge rate of the entire power storage system 100 while taking into consideration the constraint imposed by the charge rate of the third power storage device, whose temperature is predicted to be lower than the first threshold in the future.

[0062] For example, in the first modified example, the third control described above is executed, thereby shortening the charging time for the entire power storage system 100. In the embodiment, the fourth control described above is executed, thereby making it possible to appropriately charge the fourth power storage device other than the third power storage device.

[0063] [Change Example 2] The following describes Modification 2 of the embodiment, focusing mainly on the differences from the embodiment and Modification 1.

[0064] In the second modification, a case is assumed in which when the temperature of the power storage device 110 is lower than a second threshold (e.g., 60°C), the charge rate applicable to the power storage device 110 is a first charge rate (e.g., 10 A), and when the temperature of the power storage device 110 is equal to or higher than the second threshold (e.g., 60°C), the charge rate applicable to the power storage device 110 is a second charge rate (e.g., 1 A). The second charge rate is a charge rate lower than the first charge rate.

[0065] First, in the embodiment, the first power storage device is power storage device 110 whose current temperature is lower than a first threshold. In contrast, in Modification 2, the first power storage device may be power storage device 110 whose current temperature is higher than a second threshold (for example, 60°C).

[0066] That is, the controller 130 may execute a first control to disconnect a first power storage device, of the two or more power storage devices 110, whose current temperature is higher than a second threshold value, from the PCS 120. When the power storage capacity of a second power storage device other than the first power storage device, of the two or more power storage devices 110, reaches a predetermined capacity, the controller 130 may execute a second control to disconnect the second power storage device from the PCS 120 and connect the first power storage device to the PCS 120.

[0067] Second, in Modification Example 1, the third power storage device is power storage device 110 whose future temperature is predicted to be lower than the first threshold value. In contrast, in Modification Example 2, the third power storage device may be power storage device 110 whose current temperature is predicted to be higher than a second threshold value (for example, 60°C).

[0068] That is, the controller 130 may execute a third control to disconnect a fourth power storage device other than a third power storage device whose future temperature is predicted to be higher than the second threshold value based on the information related to temperature, among the two or more power storage devices 110, from the PCS 120. When the power storage capacity of the third power storage device reaches a predetermined capacity or when the current temperature of the third power storage device becomes higher than the third threshold value, the controller 130 executes a fourth control to disconnect the third power storage device from the PCS 120 and connect the fourth power storage device to the PCS 120.

[0069] [Other embodiments] Although the present disclosure has been described by the above-mentioned embodiments, the descriptions and drawings forming part of this disclosure should not be understood as limiting the present invention. From this disclosure, various alternative embodiments, examples, and operating techniques will become apparent to those skilled in the art.

[0070] In the above disclosure, a case has been exemplified in which the temperature detected by the sensor 113 is used as information regarding the temperature of each of the two or more power storage devices 110. The information regarding the temperature may be a value directly indicating the temperature, or may be a value indicating a change correlated with a temperature change (for example, a resistance value of the sensor relative to a temperature value). The resistance value of the sensor may be proportional to the temperature value, or the resistance value of the sensor may be determined by a table indicating a relationship with the temperature value. Furthermore, the information regarding the temperature may include the installation location of each of the two or more power storage devices 110, the air temperature at each of the installation locations of the two or more power storage devices 110, the solar radiation of each of the two or more power storage devices 110, or the air volume and direction of each of the two or more power storage devices 110. The installation location may be a value indicating longitude and latitude, a numerical value associated with a predetermined place name or point, or a value indicating the orientation of the power storage device 110 in the area where the power storage system 100 is installed. The air temperature may be a value of a temperature sensor correlated with the air temperature. The solar radiation may be a value of a light sensor correlated with solar radiation. The air volume may be a wind speed value. The wind direction may be a directional value indicating the wind direction. The air volume and wind direction may be values ​​of a wind speed sensor correlated with the air volume and wind direction. The installation location may be known to the power storage system 100 or may be input by an operator or the like. The air temperature and solar radiation may be obtained from an external server such as a weather server. In such a case, the temperature of the power storage device 110 may be interpreted as a temperature estimated from information related to temperature. The first power storage device may be interpreted as a power storage device whose current temperature is assumed to be lower than a first threshold value or higher than a second threshold value.

[0071] In the above disclosure, the case where the power storage system 100 has two power storage devices 110 has been exemplified. However, the above disclosure is not limited to this. The power storage system 100 may have three or more power storage devices 110.

[0072] Although not specifically mentioned in the above disclosure, the characteristics of the charge rate of the power storage device 110 may differ for each power storage device 110. For example, the charge rate may differ for each power storage device 110. The first threshold value and the second threshold value for determining whether to switch the charge rate may differ for each power storage device 110.

[0073] In the above disclosure, first, second, third, and fourth control have been exemplified as examples of priority-based connection state control. However, the above disclosure is not limited thereto. The priority-based connection state control may be control that switches the connection state so as to shorten the charging time of the entire power storage system 100, taking into account the charge rate of the first power storage device whose current temperature is lower than the first threshold or whose current temperature is higher than the second threshold. Alternatively, the priority-based connection state control may be control that switches the connection state so as to shorten the charging time of the entire power storage system 100, taking into account the charge rate of the third power storage device whose future temperature is predicted to be lower than the first threshold or higher than the second threshold.

[0074] Although not specifically mentioned in the above description, the embodiment (first control and second control) may be combined with Modified Example 1 (third control and fourth control). In such a case, the embodiment (first control and second control) and Modified Example 1 (third control and fourth control) may be combined so as to shorten the charging time of the energy storage system 100 as a whole.

[0075] Although not specifically mentioned in the above disclosure, the controller 130 may set priorities for charging two or more power storage devices when charging the power storage device 110. The controller 130 may periodically set priorities for charging two or more power storage devices. The controller 130 may select the type of information about temperature when setting the priorities. The type of information about temperature may be set in the controller 130 at the design stage or factory shipping stage of the power storage system 100.

[0076] The above disclosure may have the following problems and effects.

[0077] As described above, there may be a case where two or more power storage devices are connected in parallel to one power conversion device, and the charge rate of each of the two or more power storage devices depends on the temperature of each of the two or more power storage devices.

[0078] However, when two or more storage devices are connected in parallel to one PCS, the charge rate of each of the two or more storage devices cannot be controlled individually, and therefore the charge rate of each of the two or more storage devices is restricted by the charge rate of the storage device with the lowest temperature.

[0079] The inventors focused on the above-mentioned points and discovered that when two or more storage devices connected in parallel to one PCS include a storage device whose temperature is lower than a threshold value, the charging rate of the two or more storage devices as a whole decreases.

[0080] According to the above disclosure, it is possible to provide a storage system and a control method that can improve the overall charging rate of two or more storage devices when two or more storage devices are connected in parallel to one PCS.

[0081] [Note] The above disclosure may be expressed as follows: A first feature is a power storage system including two or more power storage devices connected in parallel to one power conversion device, and a control unit that controls a connection state between each of the two or more power storage devices and the one power conversion device, wherein the control unit sets priorities for charging the two or more power storage devices based on information regarding the temperature of each of the two or more power storage devices, and controls the connection state based on the priorities.

[0082] A second feature is the energy storage system of the first feature, wherein the information relating to temperature includes one or more pieces of information selected from the temperature of each of the two or more energy storage devices, the installation location of each of the two or more energy storage devices, the air temperature of each of the two or more energy storage devices, and solar radiation of each of the two or more energy storage devices.

[0083] A third feature is the energy storage system according to the first or second feature, wherein the control unit executes a first control to disconnect, from the one power conversion device, a first energy storage device among the two or more energy storage devices whose current temperature is lower than a first threshold value based on the information related to the temperature.

[0084] A fourth feature is a power storage system according to any one of the first to third features, wherein the control unit executes a first control to disconnect, from the one power conversion device, a first power storage device among the two or more power storage devices whose current temperature is higher than a second threshold based on the information related to the temperature.

[0085] A fifth feature is the energy storage system according to the third or fourth feature, wherein, when a storage capacity of a second storage device other than the first storage device among the two or more energy storage devices reaches a predetermined capacity, the control unit executes a second control to disconnect the second storage device from the one power conversion device and connect the first storage device to the one power conversion device.

[0086] A sixth feature is a power storage system according to any one of the first to fourth features, wherein the control unit executes a third control to disconnect a fourth storage device, other than a third storage device whose future temperature is predicted to be lower than a first threshold based on the information related to the temperature, from the one power conversion device among the two or more power storage devices.

[0087] A seventh feature is a power storage system according to any one of the first to sixth features, wherein the control unit executes a third control to disconnect a fourth storage device, other than a third storage device whose future temperature is predicted to be higher than a second threshold based on the information related to the temperature, from the one power conversion device among the two or more power storage devices.

[0088] Feature 8-1 is the energy storage system according to feature 6, wherein the control unit executes a fourth control to disconnect the third storage device from the one power conversion device and connect the fourth storage device to the one power conversion device when the storage capacity of the third storage device reaches a predetermined capacity or when the current temperature of the third storage device becomes lower than the first threshold value.

[0089] Feature 8-2 is the energy storage system according to feature 7, wherein the control unit executes a fourth control to disconnect the third storage device from the one power conversion device and connect the fourth storage device to the one power conversion device when the storage capacity of the third storage device reaches a predetermined capacity or when the current temperature of the third storage device becomes higher than the second threshold value.

[0090] A ninth feature is a control method including: a step A of setting priorities for charging two or more power storage devices based on information relating to the temperatures of each of the two or more power storage devices connected in parallel to one power conversion device; and a step B of controlling a connection state between each of the two or more power storage devices and the one power conversion device based on the priorities. [Explanation of symbols]

[0091] 100... Power storage system, 110... Power storage device, 111... Interface terminal, 112... Switch, 113... Sensor, 120... PCS, 130... Controller, 131... Acquisition unit, 132... Control unit, 141... Wiring

Claims

1. two or more power storage devices connected in parallel to one power conversion device; a control unit that controls a connection state between each of the two or more power storage devices and the one power conversion device, The control unit setting a priority order for charging the two or more power storage devices based on information about the temperatures of the two or more power storage devices; Controlling the connection state based on the priority; The control unit execute a first control to disconnect a first power storage device, of which the current temperature is lower than a first threshold value according to the information on the temperature, from the one power conversion device; or The power storage system executes first control to disconnect a first power storage device, of the two or more power storage devices, whose current temperature is higher than a second threshold value according to the information on temperature, from the one power conversion device.

2. 2. The power storage system according to claim 1, wherein the information related to temperature includes one or more pieces of information selected from the group consisting of a temperature of each of the two or more power storage devices, an installation location of each of the two or more power storage devices, an air temperature of each of the two or more power storage devices, and solar radiation of each of the two or more power storage devices.

3. 2. The power storage system according to claim 1, wherein, when a storage capacity of a second storage device other than the first storage device among the two or more power storage devices reaches a predetermined capacity, the control unit executes second control to disconnect the second storage device from the one power conversion device and connect the first storage device to the one power conversion device.

4. Two or more power storage devices connected in parallel to one power conversion device; a control unit that controls a connection state between each of the two or more power storage devices and the one power conversion device, The control unit setting a priority order for charging the two or more power storage devices based on information about the temperatures of the two or more power storage devices; Controlling the connection state based on the priority; The control unit execute a third control to disconnect a fourth power storage device other than a third power storage device whose future temperature is predicted to be lower than a first threshold value based on the information related to the temperature from the one power conversion device, among the two or more power storage devices; or The energy storage system executes third control to disconnect a fourth energy storage device other than a third energy storage device whose future temperature is predicted to be higher than a second threshold value based on the information related to the temperature from the one power conversion device, among the two or more energy storage devices.

5. 5. The power storage system according to claim 4, wherein the control unit executes a fourth control to disconnect the third storage device from the one power conversion device and connect the fourth storage device to the one power conversion device when the storage capacity of the third storage device reaches a predetermined capacity or when the current temperature of the third storage device becomes lower than the first threshold value.

6. a step A of setting priorities for charging two or more power storage devices connected in parallel to one power conversion device based on information about the temperatures of the two or more power storage devices; and a step B of controlling a connection state between each of the two or more power storage devices and the one power conversion device based on the priority order, Step B executing a first control to disconnect a first power storage device, of which the current temperature is lower than a first threshold value according to the information about the temperature, from the one power conversion device; or The control method includes a step of performing first control to disconnect a first power storage device, of the two or more power storage devices, whose current temperature is higher than a second threshold according to the information related to the temperature, from the one power conversion device.

7. A step A of setting priorities for charging two or more power storage devices connected in parallel to one power conversion device based on information about the temperatures of the two or more power storage devices; and a step B of controlling a connection state between each of the two or more power storage devices and the one power conversion device based on the priority order, Step B executing a third control to disconnect a fourth power storage device other than a third power storage device whose future temperature is predicted to be lower than a first threshold value based on the information related to the temperature, from the one power conversion device, among the two or more power storage devices; or A control method including a step of performing third control to disconnect a fourth storage device other than a third storage device whose future temperature is predicted to be higher than a second threshold value based on the information regarding the temperature from the one power conversion device, among the two or more storage devices.

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