Power storage system and restriction method

Abstract

When an abnormality occurs in the power storage unit, as much electric energy as possible can be supplied to the load within a range in which safety is ensured.SOLUTION: Power storage system 100 includes load 5 and a plurality of power storage units 10 connected to load 5. The power storage unit 10 is connected to a load 5, and includes a battery pack 20 including a plurality of battery cells 22, a contactor 30 provided between the battery pack 20 and the load 5, and a controller 50. The controller 50 includes a determination part 54 for determining whether or not abnormality occurs in the power storage unit 10, and a supply restriction part 56 for gradually restricting the maximum electric energy to be supplied to the load according to the degree of abnormality of the power storage unit 10 when the determination part 54 determines that abnormality occurs in the power storage unit 10.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an electricity storage system and a limiting method. [Background technology]

[0002] For example, Japanese Patent Application Laid-Open Publication No. 2001-185228 discloses a power supply device including multiple battery modules connected in parallel and a control circuit. Each battery module is connected in series with a current detection circuit and a switch. The control circuit is configured to switch from on to off the switch connected to a battery module where the current detected by the current detection circuit is in the opposite direction to the normal direction, or where the current imbalance is greater than a set value.

[0003] For example, Japanese Patent No. 4542536 discloses a power supply control device that controls a power storage unit. The power storage unit includes multiple series units connected in parallel. The series units include multiple power storage elements connected in series. The power supply control device includes a detection means for detecting detection information including the degree of deterioration of the series units, and a current distribution means for controlling the distribution of the amount of current passing through each series unit according to the degree of deterioration of the series units. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-185228 [Patent Document 2] Patent No. 4542536 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the case of, for example, Japanese Patent Application Laid-Open No. 2001-185228, an abnormality may occur in each battery module. Even if an abnormality occurs in a battery module, it is preferable to supply as much electric power as possible to the load within the range where safety is ensured. [Means for solving the problem]

[0006] The disclosed power storage system includes a load and a plurality of power storage units connected to the load. The power storage units include a battery pack connected to the load and including a plurality of battery cells, a contactor provided between the battery pack and the load, and a controller. The controller includes a determination unit that determines whether an abnormality has occurred in the power storage unit, and a supply limiting unit that, when the determination unit determines that an abnormality has occurred in the power storage unit, limits the maximum amount of power supplied to the load in stages depending on the degree of the abnormality in the power storage unit.

[0007] According to the power storage system disclosed herein, when an abnormality occurs in any of the power storage units among the plurality of power storage units, the maximum amount of power to be supplied to the load is limited in stages depending on the severity of the abnormality in the power storage unit. Therefore, even when an abnormality occurs in the power storage unit, it is possible to supply as much power as possible to the load depending on the type of abnormality.

[0008] The limiting method disclosed herein is a limiting method for a power storage system including a load and a plurality of power storage units connected to the load, the limiting method limiting a maximum amount of power supplied from the power storage units to the load. The power storage units include a battery pack connected to the load and including a plurality of battery cells, and a contactor provided between the battery pack and the load. The limiting method includes a determination step of determining whether an abnormality has occurred in the power storage units, and a supply limiting step of, when it is determined in the determination step that an abnormality has occurred in the power storage units, gradually limiting the maximum amount of power supplied to the load depending on the degree of the abnormality in the power storage units. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram illustrating a power storage system. [Figure 2] FIG. 1 is a block diagram of a power storage system. [Figure 3] FIG. 10 is a diagram illustrating types of abnormalities in the power storage unit. [Figure 4] FIG. 10 is a diagram illustrating threshold values ​​based on a reference upper limit voltage value. [Figure 5] FIG. 10 is a diagram illustrating threshold values ​​based on a reference lower limit voltage value. [Figure 6] 10 is a flowchart showing a procedure for detecting an abnormality in the power storage unit. [Figure 7] FIG. 10 is a diagram showing threshold values ​​based on a reference upper limit temperature. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, one embodiment of the technology disclosed herein will be described with reference to the drawings. It should be noted that the embodiment described here is not intended to limit the present invention in any way. Each drawing is a schematic diagram and does not necessarily faithfully reflect an actual product. Furthermore, the same reference numerals are appropriately used for components and parts that perform the same function, and redundant explanations will be omitted where appropriate.

[0011] FIG. 1 is a schematic diagram showing a power storage system 100 according to this embodiment. As shown in FIG. 1, the power storage system 100 includes a load 5 and a plurality of power storage units 10. In the power storage system 100, the power storage units 10 are used as power sources that supply power to the load 5. The type of the load 5 is not particularly limited. In this embodiment, the load 5 is, for example, a drive device such as an electric motor of a vehicle, or an inverter. A smoothing capacitor for reducing abrupt changes in current may be connected to the load 5. In this embodiment, there are two loads 5, a first load 5a and a second load 5b. However, the number of loads 5 may be three or more, or may be one. When there is one load 5, either the first load 5a or the second load 5b may be omitted.

[0012] In this embodiment, the power storage system 100 is mounted on a vehicle. The load 5 may be an electric motor that drives the vehicle. The specific type of vehicle is not particularly limited, but may include a ship. Because a ship may be constantly floating on water, it is preferable that the load 5 continues to operate as much as possible even if a malfunction occurs in the power storage system 100. Therefore, a plurality of loads 5 (for example, a first load 5a and a second load 5b) may be mounted on the ship. Even if a malfunction occurs in the first load 5a, the ship can still operate using the second load 5b. Note that the vehicle on which the power storage system 100 is mounted is not limited to a ship, and may be, for example, an automobile such as a hybrid vehicle, a plug-in hybrid vehicle, or an electric vehicle. Furthermore, the power storage system 100 is not limited to be used for a vehicle.

[0013] The plurality of power storage units 10 are connected in parallel. The number of power storage units 10 is not particularly limited, but is two here. The number of power storage units 10 may be three or more. The power storage unit 10 includes a first power storage unit 10a and a second power storage unit 10b. The plurality of power storage units 10 (here, the first power storage unit 10a and the second power storage unit 10b) are connected in parallel. Each power storage unit 10 is connected to a load 5, more specifically, to a first load 5a and a second load 5b. That is, the first power storage unit 10a is connected to the first load 5a and the second load 5b. The second power storage unit 10b is connected to the first load 5a and the second load 5b.

[0014] The first power storage unit 10a and the second power storage unit 10b have the same configuration. In the following description, the first power storage unit 10a and the second power storage unit 10b will be referred to as the power storage unit 10 when a common description is given. In this embodiment, as shown in FIG. 1 , the power storage unit 10 includes a battery pack 20, a contactor 30, and a controller 50.

[0015] The battery pack 20 is connected to a load 5 (here, both a first load 5a and a second load 5b). The battery pack 20 includes a plurality of battery cells 22. The battery cells 22 are chargeable and dischargeable. For example, a secondary battery that can be repeatedly charged and discharged by the movement of charge carriers between a pair of electrodes (e.g., a positive electrode and a negative electrode) via an electrolyte may be used as the battery cell 22. For example, a lithium ion secondary battery or a nickel-metal hydride battery may be used as the battery cell 22. Here, an example in which a lithium ion secondary battery is used as the battery cell 22 will be described. In this embodiment, the plurality of battery cells 22 are connected in series. Here, the plurality of battery cells 22 are connected in series via a bus bar (not shown). However, the plurality of battery cells 22 may also be connected in parallel. The number of battery cells 22 included in one battery pack 20 is not particularly limited and is a predetermined number. In this embodiment, the number of battery cells 22 included in the battery pack 20 of the first power storage unit 10a is the same as the number of battery cells 22 included in the battery pack 20 of the second power storage unit 10b, but may be different.

[0016] The contactor 30 is provided between the battery pack 20 and the load 5 (here, a first load 5a and a second load 5b). The contactor 30 is connected in series to the battery pack 20 (in other words, a plurality of battery cells 22 connected in series). The contactor 30 switches the connection between the battery pack 20 and the load 5 between ON and OFF. The contactor here is another word for a relay. In this embodiment, the contactor 30 has a first contactor 31 and a second contactor 32. The first contactor 31 is connected in series to the positive electrode end of the battery pack 20. The first contactor 31 switches the connection between the positive electrode terminal of the battery pack 20 and the load 5 between ON and OFF. The second contactor 32 is connected in series to the negative electrode end of the battery pack 20. The second contactor 32 switches the connection between the negative electrode terminal of the battery pack 20 and the load 5 between ON and OFF. In this embodiment, turning the contactor 30 ON refers to a connected state (closed state). Turning the contactor 30 OFF refers to a disconnected state (open state). In this embodiment, the contactor 30 including the first contactor 31 and the second contactor 32 is electrically switched ON and OFF.

[0017] In this embodiment, as shown in FIG. 1 , the energy storage unit 10 includes a voltage sensor 42 and a temperature sensor 44. The voltage sensor 42 detects the voltage value of the battery pack 20. Here, the voltage sensor 42 may detect the voltage value of the entire battery pack 20, or may detect the voltage value of each of the plurality of battery cells 22 included in the battery pack 20 and detect the voltage value of the battery pack 20 from the voltage values ​​of each battery cell 22. The number of voltage sensors 42 provided in each energy storage unit 10 is not particularly limited. Here, the voltage sensor 42 includes a main voltage sensor 42a and a sub-voltage sensor 42b, and each energy storage unit 10 is provided with two voltage sensors 42. The main voltage sensor 42a and the sub-voltage sensor 42b can detect voltage values ​​at approximately the same location. In each energy storage unit 10, when the energy storage unit 10 is normal, the voltages detected by the main voltage sensor 42a and the sub-voltage sensor 42b can be approximately the same value (for example, below a predetermined voltage tolerance range).

[0018] The temperature sensor 44 detects the temperature of the battery pack 20 (e.g., the surface temperature of the battery pack 20). The temperature sensor 44 may, for example, detect the temperature of each of the multiple battery cells 22 included in the battery pack 20 and detect the temperature of the battery pack 20 from the temperature of each battery cell 22. The temperature sensor 44 may, for example, detect the average of the temperatures of the battery cells 22 as the temperature of the battery pack 20. The number of temperature sensors 44 provided in each power storage unit 10 is not particularly limited. Here, as shown in FIG. 1 , the temperature sensor 44 includes a main temperature sensor 44a and a sub-temperature sensor 44b, and each power storage unit 10 is provided with two temperature sensors 44. The main temperature sensor 44a and the sub-temperature sensor 44b can detect temperatures at approximately the same location. In each power storage unit 10, when the power storage unit 10 is normal, the temperatures detected by the main temperature sensor 44a and the sub-temperature sensor 44b can be approximately the same value (e.g., below a predetermined temperature tolerance range).

[0019] The controller 50 monitors the state of the battery pack 20 and controls the charging and discharging of the battery pack 20. The controller 50 also detects an abnormality in the power storage unit 10 and performs control to gradually limit the power supplied to the load 5 depending on the degree of the abnormality in the power storage unit 10. The configuration of the controller 50 is not particularly limited. The controller 50 is, for example, a microcomputer. The controller 50 includes, for example, an I / F, a CPU, a ROM, and a RAM. The controller 50 may be configured from a single computer or multiple computers.

[0020] FIG. 2 is a block diagram of the power storage system 100. In this embodiment, as shown in FIG. 2, the controller 50 is communicatively connected to the contactors 30 (specifically, the first contactor 31 and the second contactor 32), the voltage sensors 42 (specifically, the main voltage sensor 42a and the sub-voltage sensor 42b), and the temperature sensors 44 (specifically, the main temperature sensor 44a and the sub-temperature sensor 44b). The controller 50 controls the ON / OFF switching of the contactors 30. The controller 50 acquires the voltage value of the battery pack 20 from the voltage sensor 42. The controller 50 acquires the temperature of the battery pack 20 from the temperature sensor 44. In this embodiment, the power storage system 100 is a system mounted on a vehicle. Therefore, the controller 50 is communicatively connected to a vehicle control device 80 (for example, an ECU (Engine Control Unit)) that controls the entire vehicle (for example, controls drive devices such as an electric motor during driving).

[0021] 2, the controller 50 includes a storage unit 51, a voltage acquisition unit 52, a temperature acquisition unit 53, a determination unit 54, a supply limiting unit 56, and a supply unit 58. Each of the units 51 to 58 of the controller 50 may be realized by one or more processors or may be realized by a circuit. Specific features of each of the units 51 to 58 of the controller 50 will be described later.

[0022] The configuration of the power storage system 100 according to this embodiment has been described above. However, as shown in FIG. 1 , in a system in which a plurality of power storage units 10 are connected in parallel, an abnormality may occur in each of the power storage units 10. For example, if an abnormality occurs in the first power storage unit 10a, the power supplied from the first power storage unit 10a to the load 5a may be limited. Even if an abnormality occurs in the first power storage unit 10a and the power supply from the first power storage unit 10a to the load 5 is cut off, the load 5 can be driven because power is supplied from the second power storage unit 10b to the load 5.

[0023] In this embodiment, in order to detect an abnormality in the power storage unit 10, the controller 50 in each power storage unit 10 has a monitoring function of periodically monitoring the state of the battery pack 20. For example, the controller 50 determines whether or not an abnormality has occurred in the power storage unit 10 based on the voltage value of the battery pack 20 detected by the voltage sensor 42 or the temperature of the battery pack 20 detected by the temperature sensor 44. If an abnormality has occurred in the power storage unit 10, the controller 50 limits the maximum amount of power that the corresponding power storage unit 10 can supply to the load 5.

[0024] Incidentally, there can be multiple types of abnormalities in the energy storage unit 10. Depending on the type of abnormality, it may not be necessary to cut off the power supply from the energy storage unit 10. Therefore, in this embodiment, when an abnormality occurs in the energy storage unit 10, the amount of power supplied from the energy storage unit 10 to the load 5 is limited according to the type of abnormality. Here, the supply limiting unit 56 in FIG. 2 limits the maximum amount of power to be supplied to the load 5 in stages according to the degree of the abnormality in the energy storage unit 10.

[0025] FIG. 3 is a diagram showing types of abnormalities S0 of the energy storage unit 10. In this embodiment, as shown in FIG. 3, types of abnormalities of the energy storage unit 10 include a battery abnormality S1, a battery abnormality sign S2, a monitored abnormality S3, and an acquired abnormality S4. The battery abnormality S1 refers to an abnormality of the battery pack 20. The battery abnormality S1 includes an overcharge abnormality, an overdischarge abnormality, and an overheating abnormality. The overcharge abnormality refers to a state in which the battery pack 20 is overcharged. The overdischarge abnormality refers to a state in which the battery pack 20 is overdischarged. The overheating abnormality refers to a state in which the temperature of the battery pack 20 has risen too high.

[0026] The battery abnormality sign S2 refers to a state of the battery pack 20 that is highly likely to become a battery abnormality S1. That is, the battery abnormality sign S2 refers to a state of the battery pack 20 that is highly likely to become an overcharge abnormality, a state of the battery pack 20 that is highly likely to become an overdischarge abnormality, or a state of the battery pack 20 that is highly likely to become an overheating abnormality.

[0027] The monitoring abnormality S3 refers to an abnormality in the monitoring function of the power storage unit 10. The monitoring abnormality S3 refers to an abnormality in the power storage unit 10 other than the battery pack 20. For example, the monitoring abnormality S3 occurs when the battery pack 20 is not actually in the state of the battery abnormality S1, but the battery pack 20 is determined to be abnormal due to an abnormality in the monitoring function. The monitoring abnormality S3 is, for example, an abnormality in a board that implements the controller 50. The acquisition abnormality S4 is an abnormality in a function related to monitoring or acquiring the voltage value of the battery pack 20 from the voltage sensor 42, and an abnormality in a function related to monitoring or acquiring the temperature of the battery pack 20 from the temperature sensor 44. For example, if the voltage value cannot be acquired from the voltage sensor 42 or the temperature of the battery pack 20 cannot be acquired from the temperature sensor 44, the acquisition abnormality S4 occurs. The acquisition abnormality S4 is an abnormality that occurs when the state of the battery pack 20 is periodically monitored by the monitoring function.

[0028] In the present embodiment, the voltage value of the battery pack 20 detected by the voltage sensor 42 or the temperature of the battery pack 20 detected by the temperature sensor 44 is used as a parameter for determining whether or not the energy storage unit 10 is abnormal. Here, a method for detecting an abnormality in the energy storage unit 10 using the voltage sensor 42 will first be described. FIG. 4 is a diagram showing threshold values ​​based on a reference upper limit voltage value NV11. FIG. 5 is a diagram showing threshold values ​​based on a reference lower limit voltage value NV12. In the present embodiment, a predetermined reference voltage value NV1 is set in the energy storage system 100 as shown in FIGS. 4 and 5. The reference voltage value NV1 has a reference upper limit voltage value NV11 (see FIG. 4) and a reference lower limit voltage value NV12 (see FIG. 5). The reference upper limit voltage value NV11 shown in FIG. 4 is, for example, the voltage value of the battery pack 20 when the SOC of the battery pack 20 is 100%. Here, SOC is an abbreviation for State Of Charge and indicates the state of charge of the battery pack 20. The SOC indicates the battery capacity when, for example, a fully charged state is 100% and a fully discharged state is 0%. The SOC of the battery pack 20 is the battery capacity of the entire plurality of battery cells 22 that make up the battery pack 20. The reference lower limit voltage value NV12 shown in Fig. 5 is, for example, the voltage value of the battery pack 20 when the SOC of the battery pack 20 is 0%.

[0029] Note that a specification upper limit voltage value NV21 (see FIG. 4) and a specification lower limit voltage value NV22 (see FIG. 5) are set in advance for the battery pack 20. The specification upper limit voltage value NV21 is a voltage value in specifications that is the upper limit of the battery pack 20 when the battery pack 20 is used normally. The specification upper limit voltage value NV21 is, for example, a voltage value of the battery pack 20 when the battery pack 20 is at a specification upper limit SOC, which is the upper limit of the SOC of the battery pack 20 when the battery pack 20 is used normally. The specification lower limit voltage value NV22 is a voltage value in specifications that is the lower limit of the battery pack 20 when the battery pack 20 is used normally. The specification lower limit voltage value NV22 is, for example, a voltage value of the battery pack 20 when the battery pack 20 is at a specification lower limit SOC, which is the lower limit of the SOC of the battery pack 20 when the battery pack 20 is used normally. Here, as shown in FIG. 4, the reference upper limit voltage value NV11 is a value higher than the specification upper limit voltage value NV21. As shown in FIG. 5, the reference lower limit voltage value NV12 is a value lower than the specification lower limit voltage value NV22.

[0030] In this embodiment, as shown in FIGS. 4 and 5, a battery voltage threshold TV1 for detecting a battery abnormality S1, a predictive voltage threshold TV2 for detecting a battery abnormality predictive signal S2, and an acquired voltage threshold TV4 for detecting an acquired abnormality S4 are set with respect to a reference voltage value NV1. The battery voltage threshold TV1 includes an upper battery voltage threshold TV11 (see FIG. 4) and a lower battery voltage threshold TV12 (see FIG. 5). The upper battery voltage threshold TV11 is the upper limit voltage value of the battery pack 20 when detecting the battery abnormality S1. As shown in FIG. 4, the upper battery voltage threshold TV11 is set with respect to the reference upper voltage value NV11. Here, the upper battery voltage threshold TV11 is a value higher than the reference upper voltage value NV11. The lower battery voltage threshold TV12 is the lower limit voltage value of the battery pack 20 when detecting the battery abnormality S1. As shown in FIG. 5, the lower battery voltage threshold TV12 is set with respect to the reference lower voltage value NV12. Here, the battery lower limit voltage threshold TV12 is a value lower than the reference lower limit voltage value NV12.

[0031] The predictive voltage threshold TV2 has a predictive upper limit voltage threshold TV21 (see FIG. 4) and a predictive lower limit voltage threshold TV22 (see FIG. 5). The predictive upper limit voltage threshold TV21 is the upper limit voltage value of the battery pack 20 when detecting the battery abnormality predictive value S2. As shown in FIG. 4, the predictive upper limit voltage threshold TV21 is set based on the reference upper limit voltage value NV11. Here, the predictive upper limit voltage threshold TV21 is a value higher than the reference upper limit voltage value NV11 and lower than the battery upper limit voltage threshold TV11. The predictive lower limit voltage threshold TV22 is the lower limit voltage value of the battery pack 20 when detecting the battery abnormality predictive value S2. As shown in FIG. 5, the predictive lower limit voltage threshold TV22 is set based on the reference lower limit voltage value NV12. Here, the predictive lower limit voltage threshold TV22 is a value lower than the reference lower limit voltage value NV12 and higher than the battery lower limit voltage threshold TV12.

[0032] The acquisition voltage threshold TV4 has an acquisition upper limit voltage threshold TV41 (see FIG. 4) and an acquisition lower limit voltage threshold TV42 (see FIG. 5). The acquisition upper limit voltage threshold TV41 is the upper limit voltage value of the battery pack 20 when detecting the acquisition abnormality S4. As shown in FIG. 4, the acquisition upper limit voltage threshold TV41 is set based on the reference upper limit voltage value NV11. Here, the acquisition upper limit voltage threshold TV41 is a value higher than the reference upper limit voltage value NV11 and higher than the battery upper limit voltage threshold TV11 and the predictive upper limit voltage threshold TV21. The acquisition lower limit voltage threshold TV42 is the lower limit voltage value of the battery pack 20 when detecting the acquisition abnormality S4. As shown in FIG. 5, the acquisition lower limit voltage threshold TV42 is set based on the reference lower limit voltage value NV12. Here, the acquisition lower limit voltage threshold TV42 is a value lower than the reference lower limit voltage value NV12 and lower than the battery lower limit voltage threshold TV12 and the predictive lower limit voltage threshold TV22.

[0033] In this embodiment, the specific values ​​of the reference upper limit voltage value NV11, the predictive upper limit voltage threshold TV21, the battery upper limit voltage threshold TV11, and the acquisition upper limit voltage threshold TV41 are not particularly limited. For example, the reference upper limit voltage value NV11, the predictive upper limit voltage threshold TV21, the battery upper limit voltage threshold TV11, and the acquisition upper limit voltage threshold TV41 are 4.20 V, 4.25 V, 4.35 V, and 4.98 V, respectively. Furthermore, the specific values ​​of the reference lower limit voltage value NV12, the predictive lower limit voltage threshold TV22, the battery lower limit voltage threshold TV12, and the acquisition lower limit voltage threshold TV42 are not particularly limited. For example, the reference lower limit voltage value NV12, the predictive lower limit voltage threshold TV22, the battery lower limit voltage threshold TV12, and the acquisition lower limit voltage threshold TV42 are 3.00 V, 2.50 V, 1.90 V, and 0.10 V, respectively.

[0034] Next, a procedure for detecting an abnormality in the energy storage unit 10 using the voltage of the battery pack 20 will be described with reference to the flowchart in Fig. 6. In the following explanation, a procedure for detecting an abnormality in one of the multiple energy storage units 10 will be described, but in reality, abnormality detection is performed for each of the multiple energy storage units 10.

[0035] First, in step S101 of FIG. 6, the voltage acquirer 52 of FIG. 2 acquires the voltage value V1 of the battery pack 20 of the power storage unit 10. Here, the voltage acquirer 52 acquires the voltage value V1 of the battery pack 20 from the voltage sensor 42. In this embodiment, as shown in FIG. 1, two sensors, a main voltage sensor 42a and a sub-voltage sensor 42b, are used as the voltage sensor 42. Therefore, the voltage acquirer 52 acquires the voltage value V1 of the battery pack 20 from both the main voltage sensor 42a and the sub-voltage sensor 42b. Here, for example, a voltage acquisition signal is transmitted from the voltage acquirer 52 to the voltage sensor 42. The voltage sensor 42 (here, the main voltage sensor 42a and the sub-voltage sensor 42b) that has acquired the voltage acquisition signal detects the voltage value V1 of the battery pack 20. The main voltage sensor 42a and the sub-voltage sensor 42b transmit the detected voltage value V1 to the controller 50. Thereafter, the voltage acquisition unit 52 acquires the voltage value V1 transmitted from the main voltage sensor 42a and the sub-voltage sensor 42b. The voltage value V1 of the battery pack 20 acquired by the voltage acquisition unit 52 is stored in the storage unit 51. In the following description, the voltage value V1 detected by the main voltage sensor 42a is also referred to as the main voltage value V1a. The voltage value V1 detected by the sub-voltage sensor 42b is also referred to as the sub-voltage value V1b.

[0036] In the present embodiment, the voltage acquisition unit 52 may not be able to acquire the voltage value V1 of the battery pack 20 even though it should acquire the voltage value V1. For example, the voltage acquisition unit 52 may not acquire the voltage value V1 of the battery pack 20 even if a predetermined determination time has elapsed since transmitting the voltage acquisition signal as described above. In this case, the determination unit 54 in FIG. 2 may determine that a communication abnormality has occurred in the voltage sensor 42 of the power storage unit 10. In the present embodiment, the communication abnormality of the voltage sensor 42 may be included in the monitoring abnormality S3 (see FIG. 3). When the determination unit 54 determines that a communication abnormality has occurred in the voltage sensor 42 of the power storage unit 10, the power storage unit 10 may be considered to be experiencing a monitoring abnormality S3, and step S109 (see FIG. 6), which will be described later, may be executed.

[0037] If the voltage value V1 of the battery pack 20 is acquired by the voltage acquisition unit 52 in step S101, the process proceeds to step S103 in FIG. 6. In step S103, the determination unit 54 in FIG. 2 determines whether or not the power storage unit 10 is in an acquisition abnormality S4. Here, the determination unit 54 compares the voltage value V1 of the battery pack 20 with an acquisition voltage threshold TV4 (see FIGS. 4 and 5) to determine whether or not the acquisition abnormality S4 has occurred. In this embodiment, the determination unit 54 determines whether or not the voltage value V1 of the battery pack 20 (here, the main voltage value V1a and the sub-voltage value V1b) acquired by the voltage acquisition unit 52 is equal to or greater than an acquisition upper limit voltage threshold TV41 shown in FIG. 4 and whether or not it is equal to or less than an acquisition lower limit voltage threshold TV42 shown in FIG. 5. Here, if at least one of the main voltage value V1a and the sub-voltage value V1b is equal to or greater than the acquisition upper limit voltage threshold TV41 or equal to or less than the acquisition lower limit voltage threshold TV42, the determination unit 54 determines that the energy storage unit 10 is experiencing an acquisition abnormality S4. If it is determined that the energy storage unit 10 is experiencing an acquisition abnormality S4, the process proceeds to step S105 in FIG. 6.

[0038] In step S105, the supply limiting unit 56 of FIG. 2 limits the maximum amount of power to be supplied to the load 5. For example, when the power storage unit 10 is normal, the maximum amount of power to be supplied from the power storage unit 10 to the load 5 is set to a reference amount of power NP1. The reference amount of power NP1 can be changed depending on the SOC or temperature of the battery pack 20. When it is determined that the power storage unit 10 is in an acquisition abnormality S4, the supply limiting unit 56 limits the maximum amount of power to be supplied to the load 5 so that the maximum amount of power is a predetermined acquisition abnormality rate P4 relative to the reference amount of power NP1. That is, when the power storage unit 10 is in an acquisition abnormality S4, the maximum amount of power to be supplied to the load 5 is limited to the reference amount of power NP1 × the acquisition abnormality rate P4. When the power storage unit 10 is in an acquisition abnormality S4, the supply limiting unit 56 keeps the contactors 30 (here, the first contactor 31 and the second contactor 32) of the power storage unit 10 ON, i.e., maintains them in a connected, closed state. The specific value of the acquired abnormality rate P4 is not particularly limited, but is, for example, 50%.

[0039] On the other hand, in step S103 of FIG. 6, if both the main voltage value V1a and the sub-voltage value V1b are less than the acquisition upper limit voltage threshold TV41 and greater than the acquisition lower limit voltage threshold TV42, the determination unit 54 determines that the energy storage unit 10 is not experiencing an acquisition abnormality S4. If it is determined that the energy storage unit 10 is not experiencing an acquisition abnormality S4, the process proceeds to step S107 of FIG. 6. In step S107, the determination unit 54 determines whether the energy storage unit 10 is experiencing a monitoring abnormality S3. Here, the determination unit 54 determines whether the difference between the main voltage value V1a and the sub-voltage value V1b is equal to or greater than a predetermined monitoring voltage threshold TV3 (see FIG. 2). The monitoring voltage threshold TV3 is pre-stored in the storage unit 51. For example, if the difference between the main voltage value V1a and the sub-voltage value V1b is equal to or greater than the monitoring voltage threshold TV3, it becomes unclear which of the main voltage value V1a and the sub-voltage value V1b is the accurate voltage value of the battery pack 20. In this case, the determining unit 54 determines that the power storage unit 10 is in a monitoring abnormality S3. If it is determined that the power storage unit 10 is in a monitoring abnormality S3, the process proceeds to step S109 in FIG.

[0040] In step S109, the supply limiting unit 56 of FIG. 2 limits the maximum amount of power to be supplied to the load 5 when the monitoring abnormality S3 occurs. When it is determined that the power storage unit 10 has the monitoring abnormality S3, the supply limiting unit 56 limits the maximum amount of power to be supplied to the load 5 so that the maximum amount of power is equal to a predetermined monitoring abnormality rate P3 relative to the reference power amount NP1. That is, when the power storage unit 10 has the monitoring abnormality S3, the maximum amount of power to be supplied to the load 5 is limited to the reference power amount NP1 × the monitoring abnormality rate P3. When the power storage unit 10 has the monitoring abnormality S3, the supply limiting unit 56 keeps the contactors 30 (here, the first contactor 31 and the second contactor 32) of the power storage unit 10 ON, i.e., maintains them in a connected, closed state. Here, the monitoring abnormality rate P3 is a rate smaller than the acquired abnormality rate P4. The specific value of the monitoring abnormality rate P3 is not particularly limited, but is, for example, 30%. In the case of such a monitored abnormality S3, an open request may be issued to put the contactor 30 into an open state.

[0041] On the other hand, in step S107 of FIG. 6, if the difference between the main voltage value V1a and the sub-voltage value V1b is less than the monitoring voltage threshold TV3, it can be said that the difference between the main voltage value V1a and the sub-voltage value V1b is small and both voltage values ​​are correct. In this case, the determination unit 54 determines that the power storage unit 10 is not experiencing a monitoring abnormality S3. If it is determined that the power storage unit 10 is not experiencing a monitoring abnormality S3, the process proceeds to step S111 of FIG. 6. In step S111, the determination unit 54 of FIG. 2 determines whether the power storage unit 10 is experiencing a battery abnormality S1. Here, the determination as to whether the battery abnormality S1 has occurred is made by comparing the voltage value V1 of the battery pack 20 with the battery voltage threshold TV1 (see FIGS. 4 and 5). In the present embodiment, the determination unit 54 determines whether the voltage value V1 (here, the main voltage value V1a and the sub-voltage value V1b) of the battery pack 20 acquired by the voltage acquisition unit 52 is equal to or greater than the upper battery voltage threshold TV11 (see FIG. 4), and whether it is equal to or less than the lower battery voltage threshold TV12 (see FIG. 5). Here, if at least one of the main voltage value V1a and the sub-voltage value V1b is equal to or greater than the upper battery voltage threshold TV11 or equal to or less than the lower battery voltage threshold TV12, the determination unit 54 determines that the power storage unit 10 has a battery abnormality S1. If it is determined that the power storage unit 10 has a battery abnormality S1, the process proceeds to step S113 in FIG. 6.

[0042] 2 limits the maximum amount of power to be supplied to the load 5 when the battery abnormality S1 occurs. Here, because an abnormality has occurred in the battery pack 20, the supply limiting unit 56 does not supply power to the load 5, that is, limits the maximum amount of power to be supplied to the load 5 to 0. In this embodiment, as shown in FIG. 1, the supply limiting unit 56 controls the contactors 30 (here, the first contactor 31 and the second contactor 32) of the power storage unit 10 to be OFF, that is, to an open state where they are not connected.

[0043] In step S111 of FIG. 6, if both the main voltage value V1a and the sub-voltage value V1b are less than the upper battery voltage threshold TV11 and greater than the lower battery voltage threshold TV12, the determination unit 54 determines that the power storage unit 10 is not experiencing a battery abnormality S1. If it is determined that the power storage unit 10 is not experiencing a battery abnormality S1, the process proceeds to step S115 of FIG. 6. In step S115, the determination unit 54 of FIG. 2 determines whether the power storage unit 10 is experiencing a battery abnormality predictor S2. Here, the determination as to whether the power storage unit 10 is experiencing a battery abnormality predictor S2 is made by comparing the voltage value V1 of the battery pack 20 with the predictor voltage threshold TV2 (see FIGS. 4 and 5). In the present embodiment, the determination unit 54 determines whether the voltage value V1 (here, the main voltage value V1a and the sub-voltage value V1b) of the battery pack 20 acquired by the voltage acquisition unit 52 is equal to or greater than the predictive upper-limit voltage threshold TV21 (see FIG. 4), and whether it is equal to or less than the predictive lower-limit voltage threshold TV22 (see FIG. 5). Here, if at least one of the main voltage value V1a and the sub-voltage value V1b is equal to or greater than the predictive upper-limit voltage threshold TV21 or equal to or less than the predictive lower-limit voltage threshold TV22, the determination unit 54 determines that the power storage unit 10 is in the battery abnormality predictive state S2. If the power storage unit 10 is determined to be in the battery abnormality predictive state S2, the process proceeds to step S117 in FIG. 6.

[0044] 2 limits the maximum amount of power to be supplied to the load 5 when the battery abnormality prediction S2 is detected. When it is determined that the power storage unit 10 is in the battery abnormality prediction S2 state, the supply limiting unit 56 limits the maximum amount of power to be supplied to the load 5 so that the maximum amount of power is equal to a predetermined abnormality prediction rate P2 relative to the reference power amount NP1. That is, when the power storage unit 10 is in the battery abnormality prediction S2 state, the maximum amount of power to be supplied to the load 5 is limited to the reference power amount NP1 × abnormality prediction rate P2. When the power storage unit 10 is in the battery abnormality prediction S2 state, the supply limiting unit 56 keeps the contactors 30 (here, the first contactor 31 and the second contactor 32) of the power storage unit 10 ON, i.e., maintains them in a connected closed state.

[0045] In step S115 of FIG. 6, if both the main voltage value V1a and the sub-voltage value V1b are less than the predictive upper-limit voltage threshold TV21 and greater than the predictive lower-limit voltage threshold TV22, the determination unit 54 determines that the power storage unit 10 is not experiencing a battery abnormality predictor S2. In this case, the determination unit 54 determines that no abnormality has occurred in the power storage unit 10 and that the power storage unit 10 is normal. If it is determined that the power storage unit 10 is normal, the process proceeds to step S119 of FIG. 6. In step S119, the supply unit 58 of FIG. 2 does not impose a limit on the maximum amount of power to be supplied to the load 5. In other words, if the power storage unit 10 is normal, the supply unit 58 controls the maximum amount of power to be supplied to the load 5 to be equal to the reference amount of power NP1. When the power storage unit 10 is normal, the supply unit 58 keeps the contactors 30 (here, the first contactor 31 and the second contactor 32) of the power storage unit 10 ON, i.e., maintains the connected closed state. As described above, it is possible to determine whether or not there is an abnormality in the power storage unit 10 using the voltage value V1 of the battery pack 20 in accordance with the flowchart of FIG.

[0046] In this embodiment, it is possible to detect an abnormality in the energy storage unit 10 based on the temperature of the battery pack 20. Next, a method for detecting an abnormality in the energy storage unit 10 using the temperature sensor 44 will be described. FIG. 7 is a diagram showing thresholds based on a reference upper limit temperature NT1. In this embodiment, as shown in FIG. 7, a predetermined reference upper limit temperature NT1 and a specification upper limit temperature NT2 are set in the energy storage system 100. The reference upper limit temperature NT1 is a reference value for the temperature of the battery pack 20 for detecting an abnormality in the energy storage unit 10. The specification upper limit temperature NT2 is the upper limit temperature in the specifications of the battery pack 20 when the battery pack 20 is used normally. Here, the reference upper limit temperature NT1 is a value higher than the specification upper limit temperature NT2.

[0047] In this embodiment, a battery upper limit temperature threshold TT1 for detecting a battery abnormality S1, a predictive upper limit temperature threshold TT2 for detecting a battery abnormality predictor S2, and an acquisition upper limit temperature threshold TT4 for detecting an acquisition abnormality S4 are set based on a reference upper limit temperature NT1. The battery upper limit temperature threshold TT1 is the upper limit temperature of the battery pack 20 when detecting a battery abnormality S1. The battery upper limit temperature threshold TT1 is set based on the reference upper limit temperature NT1. Here, the battery upper limit temperature threshold TT1 is a value higher than the reference upper limit temperature NT1.

[0048] The predictive upper limit temperature threshold TT2 is the upper limit temperature of the battery pack 20 when detecting the battery abnormality predictive sign S2. The predictive upper limit temperature threshold TT2 is set based on the reference upper limit temperature NT1. Here, the predictive upper limit temperature threshold TT2 is a value higher than the reference upper limit temperature NT1 and lower than the battery upper limit temperature threshold TT1. The acquisition upper limit temperature threshold TT4 is the upper limit temperature of the battery pack 20 when detecting the acquisition abnormality S4. The acquisition upper limit temperature threshold TT4 is set based on the reference upper limit temperature NT1. Here, the acquisition upper limit temperature threshold TT4 is a value higher than the reference upper limit temperature NT1 and higher than the battery upper limit temperature threshold TT1 and the predictive upper limit temperature threshold TT2.

[0049] Next, a procedure for detecting an abnormality in the power storage unit 10 using the temperature of the battery pack 20 will be described with reference to the flowchart of Fig. 6, similar to the case of detecting an abnormality in the power storage unit 10 using the voltage value of the battery pack 20. Note that the processes of steps S105, S109, S113, S117, and S119 are the same as those in the case of detecting an abnormality in the power storage unit 10 using the voltage value V1 of the battery pack 20, and therefore will not be described here.

[0050] First, in step S101 of FIG. 6, the temperature acquisition unit 53 of FIG. 2 acquires the temperature T1 of the battery pack 20 of the power storage unit 10. Here, the temperature acquisition unit 53 acquires the temperature T1 of the battery pack 20 from the temperature sensor 44. In the present embodiment, as shown in FIG. 1, two sensors, a main temperature sensor 44a and a sub-temperature sensor 44b, are used as the temperature sensor 44. Therefore, the temperature acquisition unit 53 acquires the temperature T1 of the battery pack 20 from both the main temperature sensor 44a and the sub-temperature sensor 44b. Here, for example, a temperature acquisition signal is transmitted from the temperature acquisition unit 53 to the temperature sensor 44. The temperature sensor 44 (here, the main temperature sensor 44a and the sub-temperature sensor 44b) that has acquired the temperature acquisition signal detects the temperature T1 of the battery pack 20. The main temperature sensor 44a and the sub-temperature sensor 44b transmit the detected temperature T1 of the battery pack 20 to the controller 50. Thereafter, the temperature acquisition unit 53 acquires the temperature T1 of the battery pack 20 transmitted from the main temperature sensor 44a and the sub-temperature sensor 44b. The temperature of the battery pack 20 acquired by the temperature acquisition unit 53 is stored in the storage unit 51 of FIG. 2. In the following description, the temperature detected by the main temperature sensor 44a is also referred to as the main temperature T1a. The temperature detected by the sub-temperature sensor 44b is also referred to as the sub-temperature T1b.

[0051] In the present embodiment, similar to the voltage acquisition unit 52, the temperature acquisition unit 53 may not be able to acquire the temperature T1 of the battery pack 20 even though the temperature acquisition unit 53 acquires the temperature T1. For example, the temperature acquisition unit 53 may not acquire the temperature T1 of the battery pack 20 even when a predetermined determination time has elapsed since the temperature acquisition signal was transmitted as described above. In this case, the determination unit 54 in FIG. 2 may determine that a communication abnormality has occurred in the temperature sensor 44 of the power storage unit 10. In the present embodiment, as described above, when the determination unit 54 determines that a communication abnormality has occurred in the temperature sensor 44 of the power storage unit 10, the power storage unit 10 may be determined to be in a monitoring abnormality S3, and step S109 in FIG. 6 may be executed next.

[0052] If the temperature T1 of the battery pack 20 is acquired by the temperature acquisition unit 53 in step S101, the process proceeds to step S103 in FIG. 6. In step S103, the determination unit 54 in FIG. 2 compares the temperature T1 of the battery pack 20 with the acquisition upper limit temperature threshold TT4 (see FIG. 7) to determine whether or not an acquisition abnormality S4 has occurred. In the present embodiment, the determination unit 54 determines whether or not the temperature T1 (here, the main temperature T1a and the sub-temperature T1b) of the battery pack 20 acquired by the temperature acquisition unit 53 is equal to or higher than the acquisition upper limit temperature threshold TT4. Here, if at least one of the main temperature T1a and the sub-temperature T1b is equal to or higher than the acquisition upper limit temperature threshold TT4, the determination unit 54 determines that the power storage unit 10 has an acquisition abnormality S4, and the process proceeds to step S105 in FIG. 6.

[0053] On the other hand, in step S103 of FIG. 6, if both the main temperature T1a and the sub-temperature T1b are less than the upper temperature acquisition threshold TT4, the determination unit 54 determines that the power storage unit 10 is not experiencing an acquisition abnormality S4. If it is determined that the power storage unit 10 is not experiencing an acquisition abnormality S4, the process proceeds to step S107 of FIG. 6. In step S107, the determination unit 54 determines whether the difference between the main temperature T1a and the sub-temperature T1b is equal to or greater than a predetermined monitoring temperature threshold TT3 (see FIG. 2). The monitoring temperature threshold TT3 is pre-stored in the storage unit 51. For example, if the difference between the main temperature T1a and the sub-temperature T1b is equal to or greater than the monitoring temperature threshold TT3, it becomes unclear which of the main temperature T1a and the sub-temperature T1b represents the accurate temperature of the battery pack 20. In this case, the determination unit 54 determines that the power storage unit 10 is experiencing a monitoring abnormality S3. If it is determined that the power storage unit 10 is in the monitoring abnormality S3, the process proceeds to step S109 in FIG.

[0054] On the other hand, in step S107 of FIG. 6, if the difference between the main temperature T1a and the sub-temperature T1b is less than the monitoring temperature threshold TT3, the difference between the main temperature T1a and the sub-temperature T1b is small, and both temperatures can be said to be correct. In this case, the determination unit 54 determines that the power storage unit 10 is not in a monitoring abnormality S3, and the process proceeds to step S111 of FIG. 6. In step S111, the determination unit 54 compares the temperature T1 of the battery pack 20 with the battery upper limit temperature threshold TT1 (see FIG. 7) to determine whether or not a battery abnormality S1 has occurred. In this embodiment, the determination unit 54 determines whether or not the temperature T1 of the battery pack 20 (here, the main temperature T1a and the sub-temperature T1b) acquired by the temperature acquisition unit 53 is equal to or higher than the battery upper limit temperature threshold TT1. Here, if at least one of the main temperature T1a and the sub-temperature T1b is equal to or higher than the battery upper limit temperature threshold TT1, the determination unit 54 determines that the power storage unit 10 is experiencing a battery abnormality S1, and the process proceeds to step S113 in FIG.

[0055] On the other hand, in step S111 of FIG. 6, if both the main temperature T1a and the sub-temperature T1b are less than the upper battery temperature threshold TT1, the determination unit 54 determines that the power storage unit 10 is not in a battery abnormality S1 state, and the process proceeds to step S115 of FIG. 6. In step S115, the determination unit 54 compares the temperature T1 of the battery pack 20 with the predictive upper temperature threshold TT2 (see FIG. 7) to determine whether the battery pack 20 is in a battery abnormality predictive state S2. In the present embodiment, the determination unit 54 determines whether the temperature T1 of the battery pack 20 (here, the main temperature T1a and the sub-temperature T1b) acquired by the temperature acquisition unit 53 is equal to or greater than the predictive upper temperature threshold TT2. Here, if at least one of the main temperature T1a and the sub-temperature T1b is equal to or greater than the predictive upper temperature threshold TT2, the determination unit 54 determines that the power storage unit 10 is in a battery abnormality predictive state S2, and the process proceeds to step S117 of FIG. 6.

[0056] On the other hand, if both the main temperature T1a and the sub-temperature T1b are lower than the predictive upper limit temperature threshold TT2 in step S115 of Fig. 6, the determination unit 54 determines that the power storage unit 10 is not in the battery abnormality predictive state S2, and proceeds to step S119. As described above, it is possible to determine whether or not there is an abnormality in the power storage unit 10 using the temperature T1 of the battery pack 20 in accordance with the flowchart of Fig. 6.

[0057] As described above, in this embodiment, as shown in FIG. 1 , the energy storage system 100 includes a load 5 and a plurality of energy storage units 10 connected to the load 5. Each energy storage unit 10 includes a battery pack 20 connected to the load 5 and including a plurality of battery cells 22, a contactor 30 provided between the battery pack 20 and the load 5, and a controller 50. As shown in FIG. 2 , the controller 50 includes a determination unit 54 and a supply limiting unit 56. The determination unit 54 determines whether or not an abnormality S0 (see FIG. 3 ) has occurred in the energy storage unit 10. When the determination unit 54 determines that an abnormality S0 has occurred in the energy storage unit 10, the supply limiting unit 56 limits the maximum amount of power supplied to the load 5 in stages depending on the severity of the abnormality S0 of the energy storage unit 10. As a result, when an abnormality S0 has occurred in any of the plurality of energy storage units 10, the maximum amount of power supplied to the load 5 is limited in stages depending on the severity of the abnormality S0 of the energy storage unit 10 in which the abnormality has occurred. Therefore, even if an abnormality S0 occurs in the power storage unit 10, it is possible to supply as much electric power as possible to the load 5 according to the type of abnormality S0.

[0058] In this embodiment, as shown in FIG. 1, the power storage system 100 includes a voltage sensor 42 that detects a voltage value V1 of the battery pack 20. As shown in FIG. 3, the abnormality S0 of the battery pack 20 includes a battery abnormality S1, which is an abnormality of the battery pack 20, and a battery abnormality prediction S2, which indicates a state in which the battery pack 20 is likely to become the battery abnormality S1. As shown in FIG. 2, the controller 50 includes a voltage acquisition unit 52 and a supply unit 58. The voltage acquisition unit 52 acquires the voltage value V1 of the battery pack 20 in step S101 of FIG. 6. When the power storage unit 10 is normal, the supply unit 58 sets the maximum amount of power supplied from the power storage unit 10 to the load 5 to a predetermined reference amount of power NP1 in step S119 of FIG. 6. The determination unit 54 determines that the power storage unit 10 has a battery abnormality S1 when the voltage value V1 of the battery pack 20 acquired by the voltage acquisition unit 52 is equal to or greater than a predetermined upper battery voltage threshold TV11 (see FIG. 4). Furthermore, the determination unit 54 determines that the power storage unit 10 has a battery abnormality S1 when the voltage value V1 of the battery pack 20 is equal to or lower than a predetermined battery lower limit voltage threshold TV12 (see FIG. 5 ). When the determination unit 54 determines that the power storage unit 10 has a battery abnormality S1, the supply limiting unit 56 controls the power storage unit 10 not to supply power to the load 5 in step S113 of FIG. 6 . In this manner, by comparing the voltage value V1 of the battery pack 20 with the battery upper limit voltage threshold TV11 and the battery lower limit voltage threshold TV12, the battery abnormality S1 of the power storage unit 10 can be detected. For example, even if the first power storage unit 10a has a battery abnormality S1 and the maximum amount of power that can be supplied becomes 0, the second power storage unit 10b can supply the load 5 with an amount of power equal to the reference amount of power NP1 (for example, an amount of power that is about 40% of the total maximum amount of power when the power storage system 100 is normal).

[0059] In the present embodiment, the determination unit 54 determines that the power storage unit 10 is in the battery abnormality prediction state S2 when the voltage value V1 of the battery pack 20 is equal to or greater than a predetermined predictive upper limit voltage threshold TV21 (see FIG. 4) that is smaller than the battery upper limit voltage threshold TV11, and is less than the battery upper limit voltage threshold TV11. Furthermore, the determination unit 54 determines that the power storage unit 10 is in the battery abnormality prediction state S2 when the voltage value V1 of the battery pack 20 is equal to or less than a predetermined predictive lower limit voltage threshold TV22 (see FIG. 5) that is larger than the battery lower limit voltage threshold TV12, and is greater than the battery lower limit voltage threshold TV12. When the determination unit 54 determines that the power storage unit 10 is in the battery abnormality prediction state S2, the supply limiting unit 56 limits the maximum amount of power to be supplied to the load 5 so that the maximum amount of power is equal to a predetermined predictive abnormality rate P2 relative to the reference amount of power NP1, as in step S117 of FIG. 6. Thus, by comparing the voltage value V1 of the battery pack 20 with the predictive upper voltage threshold TV21 and the predictive lower voltage threshold TV22, it is possible to detect a battery abnormality predictor S2 of the power storage unit 10. For example, even if the first power storage unit 10a is in the battery abnormality predictor S2 and the maximum amount of power that can be supplied is the reference amount of power NP1 × predictive abnormality rate P2, the second power storage unit 10b can still supply an amount of power equal to the reference amount of power NP1 to the load 5.

[0060] 3, the abnormality S0 of the power storage unit 10 includes an acquisition abnormality S4, which is an abnormality related to the voltage value V1 of the battery pack 20 acquired by the voltage acquiring unit 52. The determining unit 54 determines that the power storage unit 10 has the acquisition abnormality S4 when the voltage value V1 of the battery pack 20 acquired by the voltage acquiring unit 52 is equal to or greater than a predetermined acquisition upper limit voltage threshold TV41 (see FIG. 4) that is greater than the battery upper limit voltage threshold TV11. The determining unit 54 also determines that the power storage unit 10 has the acquisition abnormality S4 when the voltage value V1 of the battery pack 20 is equal to or less than a predetermined acquisition lower limit voltage threshold TV42 (see FIG. 5) that is smaller than the battery lower limit voltage threshold TV12. When the determination unit 54 determines that the power storage unit 10 is experiencing an acquisition abnormality S4, the supply limiting unit 56 limits the maximum amount of power to be supplied to the load 5 in step S105 of FIG. 6 so that the maximum amount of power is equal to a predetermined acquisition abnormality rate P4 relative to the reference amount of power NP1. Here, the acquisition abnormality rate P4 is smaller than the predictive abnormality rate P2. This makes it possible to detect the acquisition abnormality S4 of the power storage unit 10 by comparing the voltage value V1 of the battery pack 20 with the acquisition upper limit voltage threshold TV41 and the acquisition lower limit voltage threshold TV42. For example, even if the first power storage unit 10a is experiencing an acquisition abnormality S4 and the maximum amount of power that can be supplied is equal to the reference amount of power NP1 × the acquisition abnormality rate P4, the second power storage unit 10b can still supply an amount of power equal to the reference amount of power NP1 to the load 5.

[0061] In this embodiment, as shown in FIG. 1, the voltage sensor 42 includes a main voltage sensor 42a and a sub-voltage sensor 42b. The voltage acquisition unit 52 acquires a main voltage value V1a detected by the main voltage sensor 42a and a sub-voltage value V1b detected by the sub-voltage sensor 42b. The determination unit 54 determines that the energy storage unit 10 has a monitoring abnormality S3 when the difference between the main voltage value V1a and the sub-voltage value V1b is equal to or greater than a predetermined monitoring voltage threshold TV3 (see FIG. 2). When the determination unit 54 determines that the energy storage unit 10 has a monitoring abnormality S3, the supply limiting unit 56 limits the maximum amount of power supplied to the load 5 so that the maximum amount of power is equal to a predetermined monitoring abnormality rate P3 relative to the reference energy amount NP1, as in step S109 of FIG. 6. The monitoring abnormality rate P3 is smaller than the acquired abnormality rate P4. This makes it possible to detect the monitoring abnormality S3 of the energy storage unit 10 by comparing the difference between the main voltage value V1a and the sub-voltage value V1b. For example, even if the first energy storage unit 10a is in a monitoring abnormality S3 and the maximum amount of power that can be supplied is the reference amount of power NP1 x the monitoring abnormality rate P3, the second energy storage unit 10b can still supply an amount of power equal to the reference amount of power NP1 to the load 5.

[0062] In this embodiment, as shown in Fig. 4, the voltage value of the battery pack 20 when the SOC of the battery pack 20 is 100% is set to a reference upper limit voltage value NV11. The battery upper limit voltage threshold TV11 is higher than the reference upper limit voltage value NV11. Here, the predictive upper limit voltage threshold TV21 and the acquisition upper limit voltage threshold TV41 are higher than the reference upper limit voltage value NV11. Here, when the voltage value V1 of the battery pack 20 is higher than the reference upper limit voltage value NV11, it is highly likely that some kind of abnormality has occurred in the power storage unit 10. Therefore, by setting the thresholds TV11, TV21, and TV41 based on the reference upper limit voltage value NV11, it is possible to detect the battery abnormality S1, the battery abnormality predictive value S2, and the acquired abnormality S4.

[0063] In this embodiment, as shown in FIG. 5 , the voltage value of the battery pack 20 when the SOC of the battery pack 20 is 0% is set to a reference lower limit voltage value NV12. The battery lower limit voltage threshold TV12 is lower than the reference lower limit voltage value NV12. Here, the predictive lower limit voltage threshold TV22 and the acquisition lower limit voltage threshold TV42 are lower than the reference lower limit voltage value NV12. Here, when the voltage value V1 of the battery pack 20 is lower than the reference lower limit voltage value NV12, it is highly likely that some kind of abnormality has occurred in the energy storage unit 10. Therefore, by setting the thresholds TV12, TV22, and TV42 based on the reference lower limit voltage value NV12, it is possible to detect the battery abnormality S1, the battery abnormality predictive value S2, and the acquired abnormality S4.

[0064] In this embodiment, as shown in FIG. 1, the power storage unit 10 includes a temperature sensor 44 that detects the temperature T1 of the battery pack 20. A temperature acquisition unit 53 (see FIG. 2) of the controller 50 acquires the temperature of the battery pack 20. A determination unit 54 determines that the power storage unit 10 has a battery abnormality S1 when the temperature T1 of the battery pack 20 acquired by the temperature acquisition unit 53 is equal to or higher than a predetermined upper battery temperature threshold TT1 (see FIG. 7). Furthermore, the determination unit 54 determines that the power storage unit 10 has a battery abnormality abnormality predictor S2 when the temperature T1 of the battery pack 20 is equal to or higher than a predetermined upper battery temperature threshold TT2 (see FIG. 7) that is lower than the upper battery temperature threshold TT1 and is lower than the upper battery temperature threshold TT1. In this way, by comparing the temperature T1 of the battery pack 20 with the upper battery temperature threshold TT1, it is possible to detect the battery abnormality S1 of the power storage unit 10. Furthermore, by comparing the temperature T1 of the battery pack 20 with the predictive upper limit temperature threshold TT2, a battery abnormality predictive value S2 of the power storage unit 10 can be detected.

[0065] In the present embodiment, the determination unit 54 determines that the energy storage unit 10 has an acquisition abnormality S4 when the temperature T1 of the battery pack 20 acquired by the temperature acquisition unit 53 is equal to or greater than a predetermined acquisition upper limit temperature threshold TT4 (see FIG. 7 ), which is greater than the battery upper limit temperature threshold TT1. In this way, by comparing the temperature T1 of the battery pack 20 with the acquisition upper limit temperature threshold TT4, the energy storage unit 10 can detect an acquisition abnormality S4.

[0066] In this embodiment, as shown in Fig. 1, the temperature sensor 44 includes a main temperature sensor 44a and a sub-temperature sensor 44b. The temperature acquisition unit 53 acquires a main temperature T1a detected by the main temperature sensor 44a and a sub-temperature T1b detected by the sub-temperature sensor 44b. The determination unit 54 determines that the power storage unit 10 has a monitoring abnormality S3 when the difference between the main temperature T1a and the sub-temperature T1b is equal to or greater than a predetermined monitoring temperature threshold TT3 (see Fig. 2). In this way, by comparing the difference between the main temperature T1a and the sub-temperature T1b, it is possible to detect the monitoring abnormality S3 of the power storage unit 10.

[0067] This embodiment provides a limitation method for limiting the maximum amount of power supplied from the power storage units 10 to the load 5 in a power storage system 100 including a load 5 and a plurality of power storage units 10 connected to the load 5. The limitation method includes a voltage acquisition step, a temperature acquisition step, a determination step, a supply limitation step, and a supply step. Here, the limitation method is embodied by a controller 50. The voltage acquisition step, temperature acquisition step, determination step, supply limitation step, and supply step included in the limitation method are embodied by a voltage acquisition unit 52, a temperature acquisition unit 53, a determination unit 54, a supply limitation unit 56, and a supply unit 58, respectively.

[0068] The invention disclosed herein has been described in various ways. Unless otherwise specified, the embodiments described herein do not limit the present invention. Furthermore, the embodiments of the invention disclosed herein can be modified in various ways, and each component and each process described herein can be omitted or combined as appropriate, unless a particular problem arises.

[0069] As described above, this specification includes the disclosures set forth in the following sections. Section 1: Load and a plurality of power storage units connected to the load; Equipped with The power storage unit is a battery pack connected to the load and including a plurality of battery cells; a contactor provided between the battery pack and the load; A controller; Equipped with The controller a determination unit that determines whether an abnormality has occurred in the power storage unit; a supply limiting unit that, when it is determined by the determining unit that an abnormality has occurred in the power storage unit, limits in a stepwise manner a maximum amount of power to be supplied to the load in accordance with the degree of the abnormality in the power storage unit; An energy storage system equipped with

[0070] Section 2: the power storage unit includes a voltage sensor that detects a voltage value of the battery pack; The abnormality of the power storage unit includes: a battery abnormality that is an abnormality in the battery pack; a battery abnormality prediction indicating a state in which the battery pack is likely to experience the battery abnormality; and Includes The controller a voltage acquisition unit that acquires a voltage value of the battery pack; a supply unit that sets a maximum amount of power that can be supplied from the power storage unit to the load to a predetermined reference amount of power when the power storage unit is normal; Equipped with the determination unit determines that the battery abnormality occurs in the power storage unit when the voltage value of the battery pack acquired by the voltage acquisition unit is equal to or higher than a predetermined upper battery voltage threshold; the determination unit determines that the battery storage unit is experiencing the battery abnormality warning when the voltage value of the battery pack acquired by the voltage acquisition unit is equal to or greater than a predetermined predictive upper limit voltage threshold that is lower than the battery upper limit voltage threshold, and is lower than the battery upper limit voltage threshold; the supply limiting unit controls the power storage unit not to supply power to the load when the determining unit determines that the power storage unit has the battery abnormality; Item 1. The energy storage system according to item 1, wherein when the determination unit determines that the energy storage unit is in the state of a battery abnormality predictor, the supply limiting unit limits the maximum amount of energy to be supplied to the load so that the maximum amount of energy is equal to a predetermined predictor abnormality rate relative to the reference amount of energy.

[0071] Section 3: the abnormality of the power storage unit includes an acquisition abnormality that is an abnormality related to the voltage value of the battery pack acquired by the voltage acquisition unit, the determination unit determines that the power storage unit is experiencing the acquisition abnormality when the voltage value of the battery pack acquired by the voltage acquisition unit is equal to or greater than a predetermined acquisition upper limit voltage threshold that is greater than the battery upper limit voltage threshold; the supply limiting unit, when it is determined by the determining unit that the power storage unit is experiencing the power acquisition abnormality, limits the maximum amount of power to be supplied to the load so that the maximum amount of power becomes equal to a predetermined power acquisition abnormality ratio relative to the reference amount of power; 3. The power storage system according to item 2, wherein the acquired abnormality rate is smaller than the predictive abnormality rate.

[0072] Section 4: The voltage sensor includes a main voltage sensor and a sub voltage sensor, the voltage acquisition unit acquires a main voltage value detected by the main voltage sensor and a sub-voltage value detected by the sub-voltage sensor; The abnormality of the power storage unit includes a monitoring abnormality, the determination unit determines that the power storage unit is experiencing the monitoring abnormality when a difference between the main voltage value and the sub-voltage value is equal to or greater than a predetermined monitoring voltage threshold value; the supply limiting unit limits the maximum amount of power to be supplied to the load when the determining unit determines that the power storage unit is experiencing the monitoring abnormality, so that the maximum amount of power is equal to a predetermined monitoring abnormality ratio relative to the reference amount of power; Item 4. The power storage system according to item 3, wherein the monitored abnormality rate is smaller than the acquired abnormality rate.

[0073] Section 5: When the voltage value of the battery pack when the SOC of the battery pack is 100% is set as a reference upper limit voltage value, 5. The power storage system according to any one of items 2 to 4, wherein the battery upper limit voltage threshold is higher than the reference upper limit voltage value.

[0074] Item 6: the determination unit determines that the battery abnormality occurs in the power storage unit when the voltage value of the battery pack acquired by the voltage acquisition unit is equal to or lower than a predetermined lower battery voltage threshold; The energy storage system according to any one of items 2 to 5, wherein the determination unit determines that the energy storage unit is the battery abnormality predictor when the voltage value of the battery pack acquired by the voltage acquisition unit is greater than the battery lower limit voltage threshold, is equal to or less than a predetermined predictive lower limit voltage threshold, and is greater than the battery lower limit voltage threshold.

[0075] Section 7: the abnormality of the power storage unit includes an acquisition abnormality that is an abnormality related to the voltage value of the battery pack acquired by the voltage acquisition unit, the determination unit determines that the power storage unit is experiencing the acquisition abnormality when the voltage value of the battery pack acquired by the voltage acquisition unit is equal to or less than a predetermined acquisition lower limit voltage threshold that is lower than the battery lower limit voltage threshold, the supply limiting unit, when it is determined by the determining unit that the power storage unit is experiencing the power acquisition abnormality, limits the maximum amount of power to be supplied to the load so that the maximum amount of power becomes equal to a predetermined power acquisition abnormality ratio relative to the reference amount of power; 7. The power storage system according to item 6, wherein the acquired abnormality rate is smaller than the predictive abnormality rate.

[0076] Section 8: When the voltage value of the battery pack when the SOC of the battery pack is 0% is set as a reference lower limit voltage value, Item 8. The power storage system according to item 6 or 7, wherein the battery lower limit voltage threshold is lower than the reference lower limit voltage value.

[0077] Section 9: the power storage unit includes a temperature sensor that detects the temperature of the battery pack; The abnormality of the power storage unit includes: a battery abnormality that is an abnormality in the battery pack; a battery abnormality prediction indicating a state in which the battery pack is likely to experience the battery abnormality; and Contains, The controller a temperature acquisition unit that acquires the temperature of the battery pack; a supply unit that sets a maximum amount of power that can be supplied from the power storage unit to the load to a predetermined reference amount of power when the power storage unit is normal; Equipped with the determination unit determines that the battery abnormality occurs in the power storage unit when the temperature of the battery pack acquired by the temperature acquisition unit is equal to or higher than a predetermined upper battery temperature threshold; the determination unit determines that the power storage unit is experiencing the battery abnormality prediction when the temperature of the battery pack acquired by the temperature acquisition unit is equal to or greater than a predetermined predictive upper limit temperature threshold that is lower than the battery upper limit temperature threshold, and is lower than the battery upper limit temperature threshold; the supply limiting unit controls the power storage unit not to supply power to the load when the determining unit determines that the power storage unit has the battery abnormality; Item 1. The energy storage system according to item 1, wherein when the determination unit determines that the energy storage unit is in the state of a battery abnormality predictor, the supply limiting unit limits the maximum amount of energy to be supplied to the load so that the maximum amount of energy is equal to a predetermined predictor abnormality rate relative to the reference amount of energy.

[0078] Section 10: the abnormality of the power storage unit includes an acquisition abnormality that is an abnormality related to the temperature of the battery pack acquired by the temperature acquisition unit; the determination unit determines that the power storage unit is experiencing the acquisition abnormality when the temperature of the battery pack acquired by the temperature acquisition unit is equal to or greater than a predetermined acquisition upper limit temperature threshold that is greater than the battery upper limit temperature threshold; the supply limiting unit, when it is determined by the determining unit that the power storage unit is experiencing the power acquisition abnormality, limits the maximum amount of power to be supplied to the load so that the maximum amount of power becomes equal to a predetermined power acquisition abnormality ratio relative to the reference amount of power; Item 10. The power storage system according to item 9, wherein the acquired abnormality rate is smaller than the predictive abnormality rate.

[0079] Section 11: The temperature sensor includes a main temperature sensor and a sub-temperature sensor, the temperature acquisition unit acquires a main temperature detected by the main temperature sensor and a sub-temperature detected by the sub-temperature sensor; The abnormality of the power storage unit includes a monitoring abnormality, the determination unit determines that the power storage unit is experiencing the monitoring abnormality when a difference between the main temperature and the sub-temperature is equal to or greater than a predetermined monitoring temperature threshold; the supply limiting unit limits the maximum amount of power to be supplied to the load when the determining unit determines that the power storage unit is experiencing the monitoring abnormality, so that the maximum amount of power is equal to a predetermined monitoring abnormality ratio relative to the reference amount of power; Item 11. The power storage system according to item 10, wherein the monitored abnormality rate is smaller than the acquired abnormality rate.

[0080] Section 12: 1. A limiting method for limiting a maximum amount of power supplied from a power storage unit to a load in a power storage system including a load and a plurality of power storage units connected to the load, the method comprising: The power storage unit is a battery pack connected to the load and including a plurality of battery cells; a contactor provided between the battery pack and the load; Equipped with a determination step of determining whether an abnormality has occurred in the power storage unit; a supply limiting step of limiting a maximum amount of power to be supplied to the load in stages according to the degree of the abnormality of the power storage unit when it is determined in the determining step that an abnormality has occurred in the power storage unit; The restriction method includes: [Explanation of symbols]

[0081] 5. Load 10 Energy storage unit 20 Battery pack 22 battery cells 30 Contactor 42 Voltage sensor 44 Temperature Sensor 50 Controllers 51 Storage section 52 Voltage acquisition unit 53 Temperature acquisition section 54 Judgment section 56 Supply Restriction Department 58 Supply section 100 Energy Storage System S1 battery abnormality S2 Battery abnormality warning S3 monitoring error S4 acquisition error

Claims

1. Load and a plurality of power storage units connected to the load; Equipped with The power storage unit is a battery pack connected to the load and including a plurality of battery cells; a contactor provided between the battery pack and the load; A controller; Equipped with The controller a determination unit that determines whether an abnormality has occurred in the power storage unit; a supply limiting unit that, when it is determined by the determining unit that an abnormality has occurred in the power storage unit, limits in a stepwise manner a maximum amount of power to be supplied to the load in accordance with the degree of the abnormality in the power storage unit; An energy storage system equipped with

2. the power storage unit includes a voltage sensor that detects a voltage value of the battery pack; The abnormality of the power storage unit includes: a battery abnormality that is an abnormality in the battery pack; a battery abnormality prediction indicating a state in which the battery pack is likely to experience the battery abnormality; and Includes The controller a voltage acquisition unit that acquires a voltage value of the battery pack; a supply unit that sets a maximum amount of power that can be supplied from the power storage unit to the load to a predetermined reference amount of power when the power storage unit is normal; Equipped with the determination unit determines that the battery abnormality occurs in the power storage unit when the voltage value of the battery pack acquired by the voltage acquisition unit is equal to or higher than a predetermined upper battery voltage threshold; the determination unit determines that the battery storage unit is experiencing the battery abnormality warning when the voltage value of the battery pack acquired by the voltage acquisition unit is equal to or greater than a predetermined predictive upper limit voltage threshold that is lower than the battery upper limit voltage threshold, and is lower than the battery upper limit voltage threshold; the supply limiting unit controls the power storage unit not to supply power to the load when the determining unit determines that the power storage unit has the battery abnormality; 2. The energy storage system according to claim 1, wherein, when the determination unit determines that the energy storage unit is in the state of a battery abnormality predictor, the supply limiting unit limits the maximum amount of energy to be supplied to the load so that the maximum amount of energy is equal to a predetermined predictive abnormality rate relative to the reference amount of energy.

3. the abnormality of the power storage unit includes an acquisition abnormality that is an abnormality related to the voltage value of the battery pack acquired by the voltage acquisition unit, the determination unit determines that the power storage unit is experiencing the acquisition abnormality when the voltage value of the battery pack acquired by the voltage acquisition unit is equal to or greater than a predetermined acquisition upper limit voltage threshold that is greater than the battery upper limit voltage threshold; the supply limiting unit, when it is determined by the determining unit that the power storage unit is experiencing the power acquisition abnormality, limits the maximum amount of power to be supplied to the load so that the maximum amount of power becomes equal to a predetermined power acquisition abnormality ratio relative to the reference amount of power; The power storage system according to claim 2 , wherein the acquired abnormality rate is smaller than the predictive abnormality rate.

4. The voltage sensor includes a main voltage sensor and a sub voltage sensor, the voltage acquisition unit acquires a main voltage value detected by the main voltage sensor and a sub-voltage value detected by the sub-voltage sensor; The abnormality of the power storage unit includes a monitoring abnormality, the determination unit determines that the power storage unit is experiencing the monitoring abnormality when a difference between the main voltage value and the sub-voltage value is equal to or greater than a predetermined monitoring voltage threshold value; the supply limiting unit limits the maximum amount of power to be supplied to the load when the determining unit determines that the power storage unit is experiencing the monitoring abnormality, so that the maximum amount of power is equal to a predetermined monitoring abnormality ratio relative to the reference amount of power; The power storage system according to claim 3 , wherein the monitored abnormality rate is smaller than the acquired abnormality rate.

5. When the voltage value of the battery pack when the SOC of the battery pack is 100% is set as a reference upper limit voltage value, The power storage system according to claim 2 , wherein the battery upper limit voltage threshold is higher than the reference upper limit voltage value.

6. the determination unit determines that the battery abnormality occurs in the power storage unit when the voltage value of the battery pack acquired by the voltage acquisition unit is equal to or lower than a predetermined lower battery voltage threshold; 3. The power storage system according to claim 2, wherein the determination unit determines that the power storage unit is the battery abnormality predictor when the voltage value of the battery pack acquired by the voltage acquisition unit is greater than the battery lower limit voltage threshold, is equal to or less than a predetermined predictive lower limit voltage threshold, and is greater than the battery lower limit voltage threshold.

7. the abnormality of the power storage unit includes an acquisition abnormality that is an abnormality related to the voltage value of the battery pack acquired by the voltage acquisition unit, the determination unit determines that the power storage unit is experiencing the acquisition abnormality when the voltage value of the battery pack acquired by the voltage acquisition unit is equal to or less than a predetermined acquisition lower limit voltage threshold that is lower than the battery lower limit voltage threshold, the supply limiting unit, when it is determined by the determining unit that the power storage unit is experiencing the power acquisition abnormality, limits the maximum amount of power to be supplied to the load so that the maximum amount of power becomes equal to a predetermined power acquisition abnormality ratio relative to the reference amount of power; The power storage system according to claim 6 , wherein the acquired abnormality rate is smaller than the predictive abnormality rate.

8. When the voltage value of the battery pack when the SOC of the battery pack is 0% is set as a reference lower limit voltage value, The power storage system according to claim 6 , wherein the battery lower limit voltage threshold is lower than the reference lower limit voltage value.

9. the power storage unit includes a temperature sensor that detects the temperature of the battery pack; The abnormality of the power storage unit includes: a battery abnormality that is an abnormality in the battery pack; a battery abnormality prediction indicating a state in which the battery pack is likely to experience the battery abnormality; and Contains, The controller a temperature acquisition unit that acquires the temperature of the battery pack; a supply unit that sets a maximum amount of power that can be supplied from the power storage unit to the load to a predetermined reference amount of power when the power storage unit is normal; Equipped with the determination unit determines that the battery abnormality occurs in the power storage unit when the temperature of the battery pack acquired by the temperature acquisition unit is equal to or higher than a predetermined upper battery temperature threshold; the determination unit determines that the power storage unit is experiencing the battery abnormality prediction when the temperature of the battery pack acquired by the temperature acquisition unit is equal to or greater than a predetermined predictive upper limit temperature threshold that is lower than the battery upper limit temperature threshold, and is lower than the battery upper limit temperature threshold; the supply limiting unit controls the power storage unit not to supply power to the load when the determining unit determines that the power storage unit has the battery abnormality; 2. The energy storage system according to claim 1, wherein, when the determination unit determines that the energy storage unit is in the state of a battery abnormality predictor, the supply limiting unit limits the maximum amount of energy to be supplied to the load so that the maximum amount of energy is equal to a predetermined predictive abnormality rate relative to the reference amount of energy.

10. the abnormality of the power storage unit includes an acquisition abnormality that is an abnormality related to the temperature of the battery pack acquired by the temperature acquisition unit; the determination unit determines that the power storage unit is experiencing the acquisition abnormality when the temperature of the battery pack acquired by the temperature acquisition unit is equal to or greater than a predetermined acquisition upper limit temperature threshold that is greater than the battery upper limit temperature threshold; the supply limiting unit, when it is determined by the determining unit that the power storage unit is experiencing the power acquisition abnormality, limits the maximum amount of power to be supplied to the load so that the maximum amount of power becomes equal to a predetermined power acquisition abnormality ratio relative to the reference amount of power; The power storage system according to claim 9 , wherein the acquired abnormality rate is smaller than the predictive abnormality rate.

11. The temperature sensor includes a main temperature sensor and a sub-temperature sensor, the temperature acquisition unit acquires a main temperature detected by the main temperature sensor and a sub-temperature detected by the sub-temperature sensor; The abnormality of the power storage unit includes a monitoring abnormality, the determination unit determines that the power storage unit is experiencing the monitoring abnormality when a difference between the main temperature and the sub-temperature is equal to or greater than a predetermined monitoring temperature threshold; the supply limiting unit limits the maximum amount of power to be supplied to the load when the determining unit determines that the power storage unit is experiencing the monitoring abnormality, so that the maximum amount of power is equal to a predetermined monitoring abnormality ratio relative to the reference amount of power; The power storage system according to claim 10 , wherein the monitored abnormality rate is smaller than the acquired abnormality rate.

12. 1. A limiting method for limiting a maximum amount of power supplied from a power storage unit to a load in a power storage system including a load and a plurality of power storage units connected to the load, the method comprising: The power storage unit is a battery pack connected to the load and including a plurality of battery cells; a contactor provided between the battery pack and the load; Equipped with a determination step of determining whether an abnormality has occurred in the power storage unit; a supply limiting step of limiting a maximum amount of power to be supplied to the load in stages according to the degree of the abnormality of the power storage unit when it is determined in the determining step that an abnormality has occurred in the power storage unit; The restriction method includes:

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