Electricity storage management device, electricity storage device, and method for managing electricity storage device

Abstract

An abnormality in a current detection section is determined using a voltage equalization circuit. A storage management device includes a voltage detection section, a current detection section, and a voltage equalization circuit including a plurality of transformers including a first winding connected in parallel with each storage element and a second winding connected in parallel with a storage section and the current detection section, and a plurality of switch sections including at least one of a first switch connected in series with the first winding and a second switch connected in series with the second winding, and the voltage equalization circuit reduces a voltage difference between the plurality of storage elements. In a case where a first abnormality determination condition is satisfied, processing corresponding to an abnormality detection of the current detection section is performed, the first abnormality determination condition including as a necessary condition a case where a detection result of the current detection section at the time of an on / off operation of the switch section corresponding to a selected target storage element is outside a normal current range.

Description

Technical Field

[0001] This invention relates to an energy storage management device, an energy storage device, and a method for managing the energy storage device. Background Technology

[0002] Conventional energy storage devices (e.g., battery packs) are known to include an energy storage unit (e.g., a battery pack) and a current detection unit. The current detection unit is connected in series with the energy storage unit and detects the current flowing through the energy storage unit. The current detected by the current detection unit is used, for example, to determine the charging and discharging state of the energy storage unit. However, the current detection unit may sometimes fail to detect the current flowing through the energy storage unit properly due to short circuits, open circuits, or component failures in its internal circuitry.

[0003] Therefore, conventional energy storage devices have existed that can determine whether the current detection unit is normal or abnormal. In these conventional energy storage devices, a voltage divider resistor and a relay are connected in series, and these resistors and relays are connected in parallel with the energy storage unit and the current detection unit. When the relay is in the ON state, current flows through both the energy storage unit and the voltage divider resistor. Based on the voltage drop across the voltage divider resistor and the detection result of the current detection unit, it is determined whether the current detection unit is abnormal (see Patent Document 1 below).

[0004] Prior art literature

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2019-29236 Summary of the Invention

[0007] The problem that the invention aims to solve

[0008] In the aforementioned conventional energy storage devices, in order to accurately detect the current change when the relay transitions from an off state to an on state, the resistance value of the voltage divider resistor needs to be set to a relatively small value to increase the current flowing through the energy storage section and the current detection section. However, the larger the current flowing through the energy storage section and the current detection section is set to, the greater the power loss caused by the voltage divider resistor, resulting in a reduction in the remaining capacity of the energy storage device.

[0009] The purpose of this invention is to provide an energy storage management device, an energy storage device, and a management method for an energy storage unit that can solve the above-mentioned problems.

[0010] Methods for solving problems

[0011] To achieve the above objectives, the energy storage management device of the present invention is used to manage an energy storage unit composed of multiple energy storage elements connected in series. The energy storage management device includes: a voltage detection unit that detects the voltage of each of the multiple energy storage elements; a current detection unit connected in series with the energy storage unit that detects the current flowing through the energy storage unit; and a voltage equalization circuit including multiple transformers and multiple switching units. The multiple transformers are respectively arranged corresponding to the multiple energy storage elements, each having a first winding connected in parallel with each energy storage element and a second winding connected in parallel with the energy storage unit and the current detection unit. The multiple switching units are respectively arranged corresponding to the multiple energy storage elements, each having a first switch connected in series with the first winding and a second switch connected in series with the second winding. At least one of the following: the voltage equalization circuit reduces the voltage difference between the plurality of energy storage elements; the on / off control unit selects a portion of the energy storage elements as target energy storage elements, and causes the switch unit corresponding to the target energy storage element to perform an on / off operation; and the first abnormality processing unit performs processing corresponding to the abnormal detection of the current detection unit when a first abnormality judgment condition is met, wherein the first abnormality judgment condition includes the condition that the detection result of the current detection unit is outside the normal current range when the switch unit performs an on / off operation, and the normal current range is the current range corresponding to the voltage of the target energy storage element and the voltage of the energy storage unit based on the detection result of the voltage detection unit.

[0012] In this energy storage management device, when a switch section constituting a voltage equalization circuit is switched on / off, current flows in and out between the target energy storage element and the energy storage unit corresponding to that switch section. As a result, the current flowing through the energy storage unit changes. At this time, if the current detection unit is normal, the detection result of the current detection unit falls within the normal current range corresponding to the voltage of the target energy storage element and the voltage of the energy storage unit based on the detection result of the voltage detection unit; if the current detection unit is abnormal, the detection result of the current detection unit falls outside the normal current range. The inventors have newly discovered that the presence or absence of an abnormality in the current detection unit can be determined by observing the voltage change of the target energy storage element accompanying the switching on / off operation of such a voltage equalization circuit and the detection result of the current detection unit. Therefore, according to this energy storage management device, there is no need to set up a separate dedicated current path for determining whether the current detection unit is abnormal; the presence or absence of an abnormality in the current detection unit can be determined using the voltage equalization circuit.

[0013] In the aforementioned energy storage management device, the first anomaly judgment condition may also include the following condition as a necessary condition: the voltage of the target energy storage element changes during the switching action of the switch unit and the detection result of the current detection unit is outside the normal current range. According to this energy storage management device, it is possible to suppress the situation where the current detection unit is mistakenly judged as abnormal in the event of an anomaly in the voltage equalization circuit.

[0014] In the aforementioned energy storage management device, it may also be configured to include a second abnormality processing unit. When a second abnormality judgment condition is met, this second abnormality processing unit performs processing corresponding to the abnormality detection of the voltage equalization circuit. The second abnormality judgment condition includes, as a necessary condition, the voltage change of the target energy storage element accompanying the switching action of the switching unit being outside the normal voltage range. According to this energy storage management device, in addition to abnormality detection by the current detection unit, abnormality detection of the voltage equalization circuit can also be performed.

[0015] In the aforementioned energy storage management device, it can also be configured such that the on / off control unit selects the energy storage element whose voltage is outside the reference voltage range from the plurality of energy storage elements as the target energy storage element. The reference voltage range includes the average voltage value obtained by dividing the voltage of the energy storage unit by the number of energy storage elements. In this energy storage management device, the switch unit corresponding to the energy storage element whose voltage is outside the reference voltage range and requires voltage equalization processing is switched on / off, and the current detection unit is checked for any abnormality. Therefore, according to this energy storage management device, compared with the structure that selects the target energy storage element regardless of whether the voltage is within the reference voltage range, it is possible to suppress the switching on / off operation of the switch unit, which is not normally needed in the voltage equalization processing, while using the voltage equalization circuit to determine whether the current detection unit is abnormal.

[0016] In the aforementioned energy storage management device, the device may further include a third abnormality processing unit. This third abnormality processing unit, upon satisfying a third abnormality judgment condition, performs processing corresponding to the abnormality detection of the voltage equalization circuit. The third abnormality judgment condition includes at least one of the following conditions as necessary conditions: the abnormality detection results of the current detection unit differ when the same switch among the plurality of switch units is repeatedly switched on / off; and the abnormality detection results of the current detection unit differ when at least two or more switch units are sequentially switched on / off. According to this energy storage management device, in addition to the abnormality detection of the current detection unit, abnormality detection of the voltage equalization circuit can also be performed.

[0017] In the aforementioned energy storage management device, when the target energy storage element includes a first energy storage element and a second energy storage element that are adjacent to each other, the on / off control unit can perform on / off operations of the switch corresponding to the first energy storage element and the switch corresponding to the second energy storage element at different times. For example, when the on / off operations of the switch corresponding to the adjacent energy storage element are performed at the same time, the voltage drop in the common path cancels each other out, making it impossible to accurately measure the voltage of each energy storage element. As a result, it may be impossible to accurately determine whether the current detection unit is abnormal. In contrast, according to this energy storage management device, the on / off operations of the switch corresponding to the adjacent energy storage elements (first energy storage element and second energy storage element) are performed at different times, thus suppressing the decrease in accuracy of determining whether the current detection unit is abnormal.

[0018] The energy storage device of the present invention comprises an energy storage section consisting of multiple energy storage elements connected in series and any of the aforementioned energy storage management devices. According to this energy storage device, a voltage equalization circuit can be used to determine whether the current detection section is malfunctioning.

[0019] This invention relates to a management method for an energy storage device: the energy storage device comprises: an energy storage section consisting of multiple energy storage elements connected in series; a voltage detection section that detects the voltage of each of the multiple energy storage elements; a current detection section connected in series with the energy storage section that detects the current flowing through the energy storage section; and a voltage equalization circuit comprising multiple transformers and multiple switching sections, wherein the multiple transformers are respectively arranged correspondingly to the multiple energy storage elements, each having a first winding connected in parallel with each energy storage element and a second winding connected in parallel with the energy storage section and the current detection section; the multiple switching sections are respectively arranged correspondingly to the multiple energy storage elements, each having a first switch connected in series with the first winding and a second switch connected in series with the second winding. At least one of the voltage equalization circuits reduces the voltage difference between the plurality of energy storage elements. The energy storage unit management method includes the following steps: selecting a portion of the energy storage elements as target energy storage elements from the plurality of energy storage elements, and causing the switch corresponding to the target energy storage element to perform an on / off operation; and, if a first abnormality judgment condition is met, performing processing corresponding to the abnormality detection of the current detection unit. The first abnormality judgment condition includes the condition that the detection result of the current detection unit is outside the normal current range when the switch is turned on / off, and the normal current range is the current range corresponding to the voltage of the target energy storage element and the voltage of the energy storage unit based on the detection result of the voltage detection unit. According to this energy storage unit management method, the voltage equalization circuit can be used to determine whether the current detection unit is abnormal.

[0020] Furthermore, the technology disclosed in this specification can be implemented in various ways, such as by means of an energy storage management device, an energy storage device having an energy storage management device and an energy storage section, their management methods, computer programs implementing these methods, and non-transitory recording media containing the computer program. Attached Figure Description

[0021] Figure 1 This is an explanatory diagram that schematically illustrates the structure of the battery device 100 in the embodiment.

[0022] Figure 2 This is a diagram illustrating the operation of constant current control when one of the multiple batteries 12, battery 12a, is used as the target battery 12x.

[0023] Figure 3 This is an explanatory diagram showing an example of the normal current range table T1.

[0024] Figure 4 This is a flowchart illustrating the exception detection process performed in the battery device 100 of the embodiment.

[0025] Figure 5 This is a flowchart illustrating the on / off control process performed in the battery device 100 of the embodiment. Detailed Implementation

[0026] A. Implementation method:

[0027] A-1. Structure of battery device 100:

[0028] Figure 1 This is an explanatory diagram that schematically illustrates the structure of the battery device 100 in this embodiment. The battery device 100 includes a battery pack 10 and an energy management device 20.

[0029] The battery pack 10 has a structure consisting of multiple batteries 12 connected in series. In this embodiment, the battery pack 10 is composed of four batteries 12 (12a, 12b, 12c, 12d). Examples of batteries 12 include lithium-ion batteries based on iron phosphate. The battery pack 10 is connected to a load (not shown) and an external power source via a positive terminal 42 and a negative terminal 44. The battery pack 10 is an example of an energy storage unit, and the batteries 12 are examples of energy storage elements.

[0030] The energy storage management device 20 is a device for managing the battery device 100, which includes the battery pack 10. The energy storage management device 20 includes a voltage detection unit 22, a current detection unit 24, a monitoring unit 28, a voltage equalization circuit 30, a line switch 40, a control unit 60, a recording unit 72, a history unit 74, and an interface (I / F) unit 76. The battery device 100 is an example of an energy storage device.

[0031] Each battery 12 is provided with a voltage detection unit 22. Each voltage detection unit 22 is connected in parallel with each battery 12, detects the voltage of each battery 12, and outputs a signal indicating the detected voltage value to a monitoring unit 28. A current detection unit 24 is connected in series with the battery pack 10. The current detection unit 24 detects the current flowing through the battery pack 10 and outputs a signal indicating the detected current value to the monitoring unit 28. Based on the signals received from the voltage detection units 22 and the current detection units 24, the monitoring unit 28 outputs signals indicating the voltage of each battery 12 and the current flowing through the battery pack 10 to the control unit 60.

[0032] The voltage equalization circuit 30 is a circuit that performs constant current control by moving charge among the plurality of batteries 12 constituting the battery pack 10. This constant current control is used to reduce the voltage difference between the plurality of batteries 12. That is, the voltage equalization circuit 30 is a circuit used to perform voltage equalization in an active manner. The voltage equalization circuit 30 is configured not limited to a group of two adjacent batteries 12, and can perform voltage equalization on any group of batteries 12.

[0033] That is, the voltage equalization circuit 30 includes a transformer 39 for each battery 12. Each transformer 39 has a first winding 39i and a second winding 39j. The first winding 39i of each transformer 39 is connected in parallel with the corresponding battery 12. In addition, the second winding 39j of each transformer 39 is connected in parallel with the battery pack 10 and the current detection unit 24. Furthermore, the voltage equalization circuit 30 includes a first switch 37 and a second switch 38 for each battery 12. Each first switch 37 is connected in series with the first winding 39i of the transformer 39 for each battery 12, and each second switch 38 is connected in series with the second winding 39j of the transformer 39 for each battery 12. The control unit 60 controls the on / off operation of each first switch 37 and each second switch 38 through a predetermined modulation method (e.g., pulse width modulation (PWM)) to perform constant current control, thereby allowing charge to move between each battery 12 and the battery pack 10 through the transformer 39. The first switch 37 and the second switch 38 may be, for example, MOSFETs (Metal-Oxide-Semiconductor Field-Effect Transistors) or relays. Hereinafter, the first switch 37 and the second switch 38 will sometimes be collectively referred to as the "switching section".

[0034] Furthermore, in this embodiment, each battery 12 is connected to the voltage equalization circuit 30 via a wire 36. Specifically, one end of each voltage detection unit 22 is connected to the first winding 39i of each transformer 39, and its connection point is connected to the positive terminal of the battery 12 via the wire 36. Additionally, the other end of each voltage detection unit 22 is connected to the first switch 37, and its connection point is connected to the negative terminal of the battery 12 via the wire 36. The shared wire 36 is used for the movement of charge between adjacent batteries 12, thus canceling out current.

[0035] According to the voltage equalization circuit 30 with such a structure, by moving charge among the multiple batteries 12, constant current control can be performed individually on each battery 12 to reduce the voltage difference between the multiple batteries 12. That is, at least one battery 12 among the multiple batteries 12 whose voltage detected by the voltage detection unit 22 differs from the average voltage Vave of the multiple batteries 12 by a predetermined value can be identified as a target battery 12x, and constant current control is performed on the target battery 12x to make its voltage close to the average voltage Vave.

[0036] Figure 2 This is a schematic diagram illustrating the operation of constant current control when one of the multiple batteries 12, battery 12a, is used as the target battery 12x. Figure 2 In column A, it is shown that the voltage Va of battery 12a, which is the target battery 12x, is higher than the average voltage Vave of all batteries 12. This causes the first switch 37 to be turned on / off, causing charge to move from the target battery 12x to the other batteries 12, thereby achieving voltage equalization. Additionally, in Figure 2 In column B, it is shown that the voltage Va of battery 12a, which is the target battery 12x, is lower than the average voltage Vave of all batteries 12, so the second switch 38 is turned on / off, causing charge to move from other batteries 12 to the target battery 12x, thereby achieving voltage equalization.

[0037] Circuit switch 40 ( Figure 1 The circuit switch 40 is located between the current detection unit 24 and the negative terminal 44. The circuit switch 40 is controlled to be turned on / off by the control unit 60, thereby closing and opening the connection between the battery pack 10 and the load and external power source.

[0038] The control unit 60 is configured using, for example, a CPU, a multi-core CPU, a programmable gate array (FPGA), or a programmable logic device (PLD), to control the operation of the energy storage management device 20. The control unit 60 functions as an on / off control unit 62, a current detection unit malfunction handling unit 64, and an equalization circuit malfunction handling unit 66. The functions of these units will be explained in conjunction with the malfunction judgment and handling description described later. The current detection unit malfunction handling unit 64 is an example of a first malfunction handling unit, and the equalization circuit malfunction handling unit 66 is an example of a second and third malfunction handling unit.

[0039] The recording unit 72 is composed of, for example, ROM, RAM, hard disk drive (HDD), etc., and stores various programs and data, or serves as a working area or data storage area when performing various processes. For example, the recording unit 72 stores a computer program for performing the exception handling described later. This computer program is provided, for example, stored on a computer-readable recording medium (not shown) such as CD-ROM, DVD-ROM, or USB memory, and is stored in the recording unit 72 by being installed in the battery device 100.

[0040] In addition, the recording unit 72 stores a normal current range table T1. The normal current range table T1 is used to determine the normal range of the current value flowing through the battery pack 10 based on the voltage relationship between the battery 12 and the battery pack 10. Figure 3 This is an explanatory diagram showing an example of the normal current range table T1. The normal current range table T1 is a table that establishes a relationship between the terminal voltage (cell voltage) of the battery 12, the voltage of the battery pack 10 (battery pack voltage), and the normal current range. The normal current range is the numerical range of the current flowing in the battery pack 10, determined by the correspondence between the terminal voltage of the battery 12 and the voltage of the battery pack 10 under the condition that the current detection unit 24 and the voltage equalization circuit 30 can operate normally. Furthermore, in Figure 3 In the table, the normal current range is represented as l1, l2, ... etc., but in the normal current range table T1, the numerical range of the current flowing through the battery pack 10 is actually specified.

[0041] The history unit 74, for example, is composed of ROM, RAM, hard disk drive (HDD), etc., and records various histories related to the battery device 100. Examples of such histories include the anomaly detection results in the current detection unit anomaly processing unit 64 and the equalization circuit anomaly processing unit 66. The interface unit 76 communicates with other devices via wired or wireless means. For example, by communicating with other devices via the interface unit 76, the history recorded in the history unit 74 is updated.

[0042] A-2. Anomaly Detection and Handling:

[0043] Next, the abnormality detection processing performed by the energy management device 20 in the battery device 100 of this embodiment will be described. Figure 4 This is a flowchart illustrating the anomaly detection process performed in the battery device 100 of this embodiment. Figure 5 This is a flowchart illustrating the on / off control process performed in the battery device 100 of this embodiment. The anomaly detection process determines whether the current detection unit 24 and the voltage equalization circuit 30 are normal or abnormal, and performs an anomaly handling process corresponding to the determination result. The on / off control process determines whether the current detection unit 24 and the voltage equalization circuit 30 are normal or abnormal, and performs on / off operations on the switching units (first switch 37, second switch 38) corresponding to the selected target battery 12y. The anomaly detection process begins automatically, for example, when the battery device 100 is started, or according to instructions from the administrator.

[0044] When handling exceptions ( Figure 4 At the start, the on / off control unit 62 of the energy storage management device 20 ( Figure 1 The switch unit 62 selects the target battery 12y from among the multiple batteries 12 that corresponds to the switch unit performing the on / off operation (S110). For example, the target battery 12y selected by the on / off control unit 62 is the target battery 12x described above. That is, the on / off control unit 62 selects the battery 12 from among the multiple batteries 12 whose voltage is outside the reference voltage range as the target battery 12y. The reference voltage range includes the average voltage value (average voltage Vave) obtained by dividing the voltage of the battery pack 10 by the total number of batteries 12.

[0045] Next, the on / off control unit 62 of the energy storage management device 20 performs on / off control processing on the target battery 12y. Figure 5 (S120). Here, when there are multiple object batteries 12y, the adjacent object batteries 12y are switched on / off at different times, while the non-adjacent object batteries 12y are switched on / off at the same time. Specifically, in Figure 1 When all four batteries 12 shown are target batteries 12y, for example, the on / off control process is performed on batteries 12a and 12c at the same time, and then the on / off control process is performed on batteries 12b and 12d at the same time.

[0046] When the on / off control process begins, such as Figure 5 As shown, the control unit 60 of the energy storage management device 20 ( Figure 1 The system determines whether current flows through the battery pack 10 (S210). Here, as described above, this fault determination process is performed during startup when the circuit switch 40 is in the open state. Therefore, if the current detection unit 24 is functioning normally, no current should be detected in the current detection unit 24. Conversely, if current is detected in the current detection unit 24, the current detection unit 24 is in an abnormal state (e.g., a short circuit, open circuit, or component failure in the internal circuit), and may be unable to perform accurate current detection. Furthermore, the control unit 60 detects the current flowing through the battery pack 10 based on the signal input from the monitoring unit 28. If the detected current value is below a predetermined lower limit (approximately zero), it determines that no current flows through the battery pack 10; if the detected current value is above the predetermined lower limit, it determines that current flows through the battery pack 10.

[0047] If the control unit 60 determines that current is flowing through the battery pack 10 (S210: No), it determines that the current detection unit 24 is in an abnormal state (S230), does not start the switching action of the switch unit, ends the current switching control process, and enters the next step. Figure 4 S130. Furthermore, in S230, the control unit 60 may, for example, notify the outside of the detection of an abnormal state of the current detection unit 24 (hereinafter referred to as "abnormal detection") via the interface unit 76. This suppresses the situation where the switching unit corresponding to the target battery 12y still performs on / off operations despite the detection of an abnormality in the current detection unit 24.

[0048] If the control unit 60 determines that no current flows through the battery pack 10 (S210: Yes), the on / off control unit 62 causes the switch unit corresponding to the target battery 12y to perform an on / off operation (S220). In this embodiment, the on / off control unit 62 controls the on / off operation of the first switch 37 or the second switch 38 to perform constant current control that brings the voltage of the target battery 12x close to the average voltage Vave.

[0049] Next, the current detection unit 64 determines whether the voltage change of the target battery 12y is outside the normal voltage range during the switching operation of the aforementioned switch unit (S240). This determination is performed to detect abnormalities in the voltage equalization circuit 30 based on the voltage change of the target battery 12y during the switching operation of the switch unit. For example, when the voltage equalization circuit 30 is in an abnormal state (e.g., a short circuit, open circuit, or component failure in the internal circuit), the voltage change of the target battery 12y before and after the start of the switching operation of the switch unit will be outside the normal voltage range.

[0050] Specifically, when the equalization circuit malfunctions, the processing unit 66 calculates the voltage difference between the target battery 12y before the start of the switching operation and the target battery 12y after the start of the switching operation (during the switching operation), and determines whether this voltage difference is outside the normal voltage range. The normal voltage range is the voltage change of the target battery 12y before and after the start of the switching operation when the voltage equalization circuit 30 is in a normal state. The normal voltage range is, for example, a voltage range including a voltage drop value (e.g., a range of values ​​between the voltage drop value and a predetermined value), which is a voltage drop value assumed based on the internal resistance value of the target battery 12y, the resistance value of the wire 36, and the constant current value of the voltage equalization circuit 30. Furthermore, the judgment condition of S240 is an example of the second abnormal judgment condition.

[0051] If the voltage change of the target battery 12y before and after the start of the switching operation of the switch unit is determined to be outside the normal voltage range (S240: Yes), the equalization circuit malfunction processing unit 66 executes the processing corresponding to the malfunction detection of the voltage equalization circuit 30 (S260), ending this switching control process. The processing corresponding to the malfunction detection of the voltage equalization circuit 30 includes, for example, notifying the outside of the malfunction detection of the voltage equalization circuit 30 via the interface unit 76, preventing the negative terminal 44 from being closed, or preventing the execution of the voltage equalization process. In this case, the processing for detecting the malfunction of the current detection unit 24 (S270-S290) described later is not executed, and the switching operation of the switch unit corresponding to the target battery 12y is stopped (S300). This is because, when the voltage equalization circuit 30 is in an abnormal state, it is impossible to accurately determine the malfunction of the current detection unit 24.

[0052] On the other hand, if the voltage equalization circuit 30 is determined to be normal (S240: No), for example, the control unit 60 records a flag indicating that the voltage equalization circuit 30 is normal in the history unit 74 (S250). Next, the current detection unit abnormality processing unit 64 determines whether the current value flowing through the battery pack 10 is outside the normal current range when the switch corresponding to the target battery 12y is turned on / off (S270). This determination is performed to detect abnormalities in the current detection unit 24 based on the current detection value of the current flowing through the battery pack 10 when the switch is turned on / off. For example, when the current detection unit 24 is in an abnormal state, the current detection value of the current flowing through the battery pack 10 when the switch is turned on / off will be outside the normal current range.

[0053] Specifically, when the current detection unit malfunctions, the processing unit 64 refers to the normal current range table T1 ( Figure 3 The normal current range corresponding to the voltage values ​​of the target battery 12y and the battery pack 10, detected during the switching operation of the switch section, is extracted. Next, the current detection unit 64 determines whether the current detection value from the current detection unit 24 during the switching operation of the switch section is outside the extracted normal current range. Furthermore, the determination condition in S270 is an example of the first abnormality determination condition. Additionally, the voltage value of the battery pack 10 can be calculated, for example, by adding the voltage detection values ​​of all the batteries 12.

[0054] If the current detection value from the current detection unit 24 is determined to be outside the normal current range during the switching operation of the switch (S270: Yes), the current detection unit 24 is deemed abnormal. For example, the control unit 60 records a flag indicating an abnormality in the current detection unit 24 in the history unit 74 (S290), proceeds to the S300 process, and ends the current switching control process. On the other hand, if the current detection value from the current detection unit 24 is determined to be outside the normal current range during the switching operation of the switch (S270: No), the current detection unit 24 is deemed normal. For example, the control unit 60 records a flag indicating a normal current detection unit 24 in the history unit 74 (S280), proceeds to the S300 process, and ends the current switching control process.

[0055] When this on / off control process ends, such as Figure 4 As shown, the control unit 60 determines whether the on / off control process has been performed on all selected target batteries 12y (S130). If it is determined that the on / off control process has not been performed on all target batteries 12y (S130: No), the control unit 60 repeatedly performs the on / off control process on the remaining target batteries 12y (S120).

[0056] On the other hand, if it is determined that the turn-on / off control process has been performed on all target batteries 12y (S130: Yes), the equalization circuit malfunction processing unit 66 determines the multiple turn-on / off control processes performed at different times ( Figure 4 The abnormal judgment result (hereinafter referred to as "current abnormal judgment result") of the current detection unit 24 in the voltage equalization circuit 30 is consistent (S140). If the voltage equalization circuit 30 is normal, all current abnormal judgment results should be consistent. On the other hand, for example, suppose that the structure circuit of the transformer 39 and the switch unit corresponding to the battery 12a is normal in the voltage equalization circuit 30, while the structure circuit of the transformer 39 and the switch unit corresponding to the battery 12b is abnormal (e.g., open circuit, short circuit). Moreover, the batteries 12a and 12b are selected as the target battery 12y in S110, and the on / off control process is performed at different times. Figure 5 Therefore, in the on / off control processing for battery 12a, the current abnormality judgment result is normal, while in the on / off control processing for battery 12b, the current abnormality judgment result is abnormal, resulting in inconsistent current abnormality judgment results. Furthermore, when the equalization circuit malfunctions, the processing unit 66 can make a judgment based on the flags (S280, S290) indicating malfunctions of the current detection unit 24 recorded in the history unit 74. Additionally, in the abnormality judgment processing, in the on / off control processing ( Figure 5 If the condition has only been performed once, it can be judged as "yes" in S140. Furthermore, the judgment condition of S140 is an example of the third abnormal judgment condition.

[0057] If it is determined that the current anomaly judgment results among the multiple current anomaly judgment results are different from other results (S140: No), the equalization circuit anomaly processing unit 66 performs the processing corresponding to the anomaly detection of the voltage equalization circuit 30 (S160) and ends this anomaly judgment processing. The processing corresponding to the anomaly detection of the voltage equalization circuit 30 is, for example, the processing of notifying the outside of the anomaly detection of the voltage equalization circuit 30 via the interface unit 76.

[0058] On the other hand, if the current anomaly judgment result is consistent each time (S140: Yes), it is determined whether the current anomaly judgment result is abnormal (S150). If the current anomaly judgment result is determined to be abnormal (S150: Yes), the current detection unit abnormal processing unit 64 executes the processing corresponding to the abnormal detection of the current detection unit 24 (S170), and ends this anomaly judgment processing. The processing corresponding to the abnormal detection of the current detection unit 24 is, for example, notifying the outside of the abnormal detection of the current detection unit 24 via the interface unit 76, or prohibiting the charging and discharging of the battery pack 10. On the other hand, if the current anomaly judgment result is determined to be normal (S150: No), the control unit 60 records a flag indicating that the current detection unit 24 is in a normal state in the recording unit 72 (S180), and ends this anomaly judgment processing. Thus, for example, voltage equalization processing can be performed.

[0059] A-3. Effects of this implementation method:

[0060] As explained above, in the energy storage management device 20 of this embodiment, such as Figure 1 As shown, the second winding 39j of each transformer 39 is connected in parallel not only with the battery pack 10 but also with the current detection unit 24. In this structure, when a part of the switch constituting the voltage equalization circuit 30 is turned on / off, current flows in and out between the target battery 12y and the battery pack 10 corresponding to that switch. As a result, the voltage of the target battery 12y changes. At this time, if the current detection unit 24 is normal, the detection result of the current detection unit 24 will be within the normal current range ( Figure 5 S270: No), the normal current range is the current range corresponding to the voltage of the target battery 12y and the voltage of the battery pack 10 based on the detection result of the voltage detection unit 22. If the current detection unit 24 is in an abnormal state, the detection result of the current detection unit 24 will be outside the normal current range. Figure 5 S270: Yes).

[0061] The inventors have discovered a novel method to determine whether the current detection unit 24 is malfunctioning by observing the voltage changes of the target battery 12y accompanying the switching on / off operation of the voltage equalization circuit 30 and the detection results of the current detection unit 24. Therefore, according to this embodiment, there is no need to provide a separate current path specifically for determining whether the current detection unit 24 is malfunctioning; the voltage equalization circuit 30 can be used to determine whether the current detection unit 24 is malfunctioning.

[0062] In this embodiment, during the on / off control process ( Figure 5In the process, the current detection unit 24 is determined to be in an abnormal state (S290) if the voltage change of the target battery 12y accompanies the switching operation of the switch section (S240: No) and the detection result of the current detection unit 24 is outside the normal current range (S270: Yes). Therefore, according to this embodiment, it is possible to suppress the situation where the current detection unit 24 is mistakenly determined to be in an abnormal state when the voltage equalization circuit 30 is in an abnormal state.

[0063] In this embodiment, during the on / off control process ( Figure 5 In the case where it is determined that the voltage change of the target battery 12y before and after the start of the switching action of the switch unit is outside the normal voltage range (S240: Yes), the voltage equalization circuit abnormality processing unit 66 performs processing corresponding to the abnormality detection of the voltage equalization circuit 30 (S260). Therefore, according to this embodiment, in addition to the abnormality detection of the current detection unit 24, the abnormality detection of the voltage equalization circuit 30 can also be performed.

[0064] In this embodiment, in the anomaly detection and processing ( Figure 4 In this process, the on / off control unit 62 selects a battery 12 whose voltage is outside the reference voltage range from among the multiple batteries 12 as the target battery 12y (S110). That is, the switch unit corresponding to the battery 12 that needs voltage equalization is turned on / off, and the current detection unit 24 is checked for abnormalities. Thus, according to this embodiment, compared with the structure that selects the target battery 12y regardless of whether the voltage is within the reference voltage range, the on / off operation of the switch unit, which is not originally needed in the voltage equalization process, can be suppressed while the voltage equalization circuit 30 is used to check for abnormalities in the current detection unit 24.

[0065] In this embodiment, in the anomaly detection and processing ( Figure 4 In the case where it is determined that among the multiple current abnormality judgment results there is a current abnormality judgment result that is different from other results (S140: No), the equalization circuit abnormality processing unit 66 performs processing corresponding to the abnormality detection of the voltage equalization circuit 30 (S160). According to this embodiment, in addition to the abnormality detection of the current detection unit 24, the abnormality detection of the voltage equalization circuit 30 can also be performed.

[0066] As described above, in the battery device 100 of this embodiment, when the switching units corresponding to adjacent batteries 12 are switched on / off at the same time, the voltage drops in the wires 36 (resistive component) along the common path will cancel each other out, making it impossible to accurately measure the voltage of each battery 12. As a result, it may be impossible to accurately determine whether the current detection unit 24 is malfunctioning. In contrast, in this embodiment, in the malfunction detection processing ( Figure 4 In the case of multiple target batteries 12y, the system performs on / off control processing on adjacent target batteries 12y at different times. This helps to suppress any decrease in the accuracy of the current detection unit 24 in determining the presence or absence of abnormalities.

[0067] B. Variations:

[0068] The technology disclosed in this specification is not limited to the above-described embodiments and can be modified in various ways without departing from its spirit, for example, the following modifications are also possible.

[0069] The structure of the battery device 100 in the above embodiments is merely an example and can be modified in various ways. For example, in the above embodiments, the number of batteries 12 constituting the battery pack 10 can be arbitrarily changed. Furthermore, in the above embodiments, batteries 12 are exemplified as energy storage elements, but capacitors could also be used, for example. Additionally, in the above embodiments, battery pack 10 is exemplified as an energy storage unit, but a capacitor pack consisting of multiple capacitors connected in series could also be used, for example. Furthermore, in the above embodiments, the voltage equalization circuit 30 may also be structured without either the first switch 37 or the second switch 38.

[0070] Furthermore, the contents of the normal current range table T1 in the above embodiments are merely one example and can be varied in many ways. Also, it is not necessary to record the normal current range table T1 in the recording unit 72. Additionally, in the above embodiments, at least one of the functional units included in the control unit 60 may be omitted.

[0071] The anomaly detection processing described in the above embodiments is merely one example and can be modified in various ways. For example, in the above embodiments, the anomaly detection of the voltage equalization circuit 30 may not be performed. Furthermore, in the above embodiments, the anomaly detection processing may be performed in parallel with the voltage equalization processing, or it may be performed separately at a different time than the voltage equalization processing, which is performed when the voltage difference between the plurality of batteries 12 constituting the battery pack 10 is detected to be greater than a predetermined threshold. Additionally, in order to perform anomaly detection of the current detection unit 24 with high accuracy, the anomaly detection processing is performed under the condition that the circuit switch 40 is in the open state; however, the anomaly detection processing may also be performed when the circuit switch 40 is in the closed state.

[0072] In the above embodiment, during the anomaly detection process S110, the on / off control unit 62 may, for example, select any one of the multiple batteries 12 as the target battery 12y regardless of the voltage level. Furthermore, in S120, the on / off control unit 62 may perform on / off control processing on adjacent target batteries 12y at the same time.

[0073] In the above embodiment, in the S240 of the on / off control process, the voltage change of the target battery 12y accompanying the on / off operation of the switch unit is used as the amount of voltage change. It is determined whether the voltage change of the target battery 12y before and after the start of the on / off operation of the switch unit is outside the normal voltage range. However, it is not limited to this. For example, it is also possible to determine whether the voltage change of the target battery 12y is outside the normal voltage range before the start of the on / off operation of the switch unit and after the end of the on / off operation.

[0074] In the above embodiment, in S140, it is determined whether the current abnormality judgment results in the on / off control processes performed at different times for different target batteries 12y are consistent. However, for example, it is also possible to determine whether the current abnormality judgment results in the on / off control processes performed at different times for the same target battery 12y are consistent.

[0075] Label Explanation

[0076] 10: Battery pack; 12: Storage battery; 12x, 12y: Target storage battery; 20: Energy management device; 22: Voltage detection unit; 24: Current detection unit; 28: Monitoring unit; 30: Voltage equalization circuit; 36: Wire; 37: First switch; 38: Second switch; 39: Transformer; 39i: First winding; 39j: Second winding; 40: Line switch; 42: Positive terminal; 44: Negative terminal; 60: Control unit; 62: On / off control unit; 64: Current detection unit abnormality handling unit; 66: Equalization circuit abnormality handling unit; 72: Recording unit; 74: History unit; 76: Interface unit; 100: Battery device; T1: Normal current range table.

Claims

1. An energy storage management device for managing an energy storage unit composed of multiple energy storage elements connected in series, wherein, The energy storage management device includes: The voltage detection unit detects the voltage of each of the plurality of energy storage elements; A current detection unit, which is connected in series with the energy storage unit, detects the current flowing through the energy storage unit; A voltage equalization circuit includes multiple transformers and multiple switching units. The multiple transformers are respectively arranged correspondingly to the multiple energy storage elements, and each transformer has a first winding connected in parallel with each energy storage element and a second winding connected in parallel with the energy storage unit and the current detection unit. The multiple switching units are respectively arranged correspondingly to the multiple energy storage elements, and each switching unit has at least one of a first switch connected in series with the first winding and a second switch connected in series with the second winding. The voltage equalization circuit reduces the voltage difference between the multiple energy storage elements. The on / off control unit selects a portion of the energy storage elements from the plurality of energy storage elements as target energy storage elements, and causes the switch unit corresponding to the target energy storage element to perform an on / off operation; and The first abnormality processing unit performs processing corresponding to the abnormality detection of the current detection unit when the first abnormality judgment condition is met. The first abnormality judgment condition includes the condition that the detection result of the current detection unit is outside the normal current range when the switch unit is turned on / off. The normal current range is the current range corresponding to the voltage of the target energy storage element and the voltage of the energy storage unit based on the detection result of the voltage detection unit.

2. The energy storage management device according to claim 1, wherein, The first abnormal judgment condition includes the following condition as a necessary condition: the voltage of the target energy storage element changes along with the switching action of the switch and the detection result of the current detection unit is outside the normal current range.

3. The energy storage management device according to claim 1 or 2, wherein, The energy storage management device also includes a second abnormality processing unit. When the second abnormality judgment condition is met, the second abnormality processing unit performs processing corresponding to the abnormality detection of the voltage equalization circuit. The second abnormality judgment condition includes the condition that the voltage change of the target energy storage element accompanying the switching action of the switch unit is outside the normal voltage range.

4. The energy storage management device according to claim 1 or 2, wherein, The on / off control unit selects the energy storage element whose voltage is outside the reference voltage range from the plurality of energy storage elements as the target energy storage element. The reference voltage range includes the average voltage value obtained by dividing the voltage of the energy storage unit by the number of energy storage elements.

5. The energy storage management device according to claim 1 or 2, wherein, The energy storage management device also includes a third abnormality processing unit. When the third abnormality judgment condition is met, the third abnormality processing unit performs processing corresponding to the abnormality detection of the voltage equalization circuit. The third abnormality judgment condition includes at least one of the following conditions as a necessary condition: when the same switch among the plurality of switch sections is turned on / off multiple times, the abnormality detection result of the current detection unit is different; and when at least two or more switch sections are turned on / off sequentially, the abnormality detection result of the current detection unit is different.

6. The energy storage management device according to claim 1 or 2, wherein, When the target energy storage element includes a first energy storage element and a second energy storage element that are adjacent to each other, the on / off control unit performs on / off operations of the switch unit corresponding to the first energy storage element and the switch unit corresponding to the second energy storage element at different times.

7. An energy storage device comprising: An energy storage unit consisting of multiple energy storage components connected in series; and The energy storage management device according to claim 1 or 2.

8. A method for managing an energy storage device, wherein, The energy storage device has: An energy storage unit consisting of multiple energy storage components connected in series; The voltage detection unit detects the voltage of each of the plurality of energy storage elements; A current detection unit, which is connected in series with the energy storage unit, detects the current flowing through the energy storage unit; as well as A voltage equalization circuit includes multiple transformers and multiple switching units. The multiple transformers are respectively arranged corresponding to multiple energy storage elements, each having a first winding connected in parallel with each energy storage element and a second winding connected in parallel with the energy storage unit and the current detection unit. The multiple switching units are respectively arranged corresponding to the multiple energy storage elements, each having at least one of a first switch connected in series with the first winding and a second switch connected in series with the second winding. The voltage equalization circuit reduces the voltage difference between the multiple energy storage elements. The management method for the energy storage unit includes the following steps: Selecting a subset of the plurality of energy storage elements as target energy storage elements, and causing the switch unit corresponding to the target energy storage element to perform an on / off operation; and If the first abnormality judgment condition is met, processing corresponding to the abnormality detection of the current detection unit is performed. The first abnormality judgment condition includes the condition that the detection result of the current detection unit is outside the normal current range when the switch unit is turned on / off. The normal current range is the current range corresponding to the voltage of the target energy storage element and the voltage of the energy storage unit based on the detection result of the voltage detection unit.

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