Power storage system, electrical equipment, and control device

Abstract

To provide a power storage system, an electric device, and a control device, which limit transmission and reception of power between assembled batteries when an abnormality relating to the power transmission or power reception between the series-connected assembled batteries is detected.SOLUTION: In a battery pack 100, battery modules 112 to 116 include: a power transmission / reception unit for transmitting and receiving power between the battery modules; a high-potential bus 144 electrically connected to positive electrode terminals of the battery modules and electrically connected to positive electrode terminals of other battery modules via the transmission / reception units; a low potential bus 142 electrically connected to negative electrode terminals of the battery module and electrically connected to negative electrode terminals of other battery modules via the transmission / reception unit; and an abnormal operation protection element arranged between the positive electrode terminals of the battery modules and the high-potential buses or between the negative electrode terminals of the battery modules and the low-potential buses and limits the transmission / reception of the power via the transmission / reception units between the battery modules.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power storage system, an electric device, and a control device. [Background technology]

[0002] Patent Documents 1 to 3 and Non-Patent Document 1 disclose a battery module including a battery pack including a plurality of storage cells and an equalization circuit that equalizes the voltage among the plurality of storage cells of the battery pack. Patent Document 4 discloses a battery pack including a plurality of battery modules connected in series. Patent Document 5 discloses a battery protection circuit. [Prior art document] [Patent documents] [Patent Document 1] Japanese Patent Application Laid-Open No. 11-176483 [Patent Document 2] JP 2011-087377 A [Patent Document 3] JP 2013-243806 A [Patent Document 4] JP 2019-30180 A [Patent Document 5] JP 2009-183141 A [Non-patent literature] [Non-Patent Document 1] Linear Technology Corporation, "LTC3300-1 - High-Efficiency Bidirectional Multi-Cell Battery Balancer," [Online], [Retrieved July 13, 2017], Internet,<URL:http: / / www.linear-tech.co.jp / product / LTC3300-1> Summary of the Invention [Means for solving the problem]

[0003] In a first aspect of the present invention, there is provided a power storage system. The power storage system includes, for example, a first assembled battery having a plurality of first storage cells connected in series, and a power transmitting and receiving unit that transmits and receives power between a second assembled battery having a plurality of second storage cells connected in series. The power storage system includes, for example, a first power line electrically connected to a positive terminal of the first assembled battery and electrically connected to a positive terminal of the second assembled battery via the power transmitting and receiving unit. The power storage system includes, for example, a second power line electrically connected to a negative terminal of the first assembled battery and electrically connected to a negative terminal of the second assembled battery via the power transmitting and receiving unit. The power storage system includes, for example, a limiting unit disposed between the positive terminal of the first assembled battery and the first power line, or between the negative terminal of the first assembled battery and the second power line, that limits transmission and reception of power between the first assembled battery and the second assembled battery via the power transmitting and receiving unit. In the power storage system, for example, the first assembled battery and the second assembled battery are connected in series. In the above power storage system, for example, the power transmitting and receiving unit transmits and receives power between the first assembled battery and the second assembled battery via the first power line and the second power line. In the above power storage system, for example, the limiting unit limits the transmission and reception of power between the first assembled battery and the second assembled battery via the power transmitting and receiving unit when an abnormality related to power transmission or power reception of the power transmitting and receiving unit is detected.

[0004] In the above power storage system, when an abnormality in the power transmitting and receiving unit is detected, the limiting unit may (i) reduce the current flowing from the second assembled battery to the first assembled battery via the first power line compared to before the abnormality was detected, or (ii) cut off the current. In the above power storage system, the abnormality in the power transmitting and receiving unit may be detected when (i) the direction of the current in at least one of the first power line, the second power line, and the power transmitting and receiving unit is different from a predetermined direction, (ii) the magnitude of the current flowing from the first power line to the first assembled battery is greater than a predetermined value, (iii) the magnitude of the current flowing from the first assembled battery to the second power line is greater than a predetermined value, or (iv) the operation of the power transmitting and receiving unit is different from the predetermined operation.

[0005] The above-mentioned power storage system may include a short circuit connecting the positive terminal of the first assembled battery, a limiting unit, and the negative terminal of the first assembled battery in series. The above-mentioned power storage system may include a switching unit that opens and closes the short circuit. In the above-mentioned power storage system, the limiting unit may limit transmission and reception of power between the first assembled battery and the second assembled battery via the power transmitting and receiving unit when the short circuit is closed. In the above-mentioned power storage system, the switching unit may open the short circuit when no abnormality is detected in the power transmitting and receiving unit, and close the short circuit when an abnormality is detected in the power transmitting and receiving unit.

[0006] The power storage system may include a detection unit that detects an abnormality in the power transmission and reception unit. The power storage system may include an opening / closing control unit that controls the opening / closing operation of the opening / closing unit when the detection unit detects an abnormality in the power transmission and reception unit.

[0007] In the above power storage system, the limiting unit may have at least one of a fuse, an electronic fuse, a PTC thermistor, and a switching element. In the above power storage system, the power transmitting and receiving unit may include an isolated bidirectional DC-DC converter. In the above power storage system, the first assembled battery may have a first equalizer that equalizes the voltages of the multiple first storage cells. In the above power storage system, the second assembled battery may have a second equalizer that equalizes the voltages of the multiple second storage cells.

[0008] The above-mentioned power storage system may include a current control unit that controls the magnitude of the output current, which is the current output from the second assembled battery via the power transmitting and receiving unit. In the above-mentioned power storage system, the current control unit may include an overcurrent protection circuit that controls the magnitude of the output current so that the magnitude of the output current does not exceed a predetermined value. In the above-mentioned power storage system, the current control unit may include a low-voltage protection circuit that stops output from the second assembled battery when the output voltage, which is the voltage output from the second assembled battery via the power transmitting and receiving unit, is lower than a predetermined value. In the above-mentioned power storage system, the power transmitting and receiving unit may operate using power supplied from the first power line and the second power line.

[0009] The power storage system may include a first assembled battery. The power storage system may include a second assembled battery.

[0010] In a second aspect of the present invention, there is provided an electric device. The electric device includes, for example, the power storage system according to the first aspect. The electric device includes, for example, a load that uses the power of the power storage system. The electric device may be a mobile object that moves using the power of the power storage system.

[0011] A third aspect of the present invention provides a control device. The control device controls, for example, a power storage system. In the control device, the power storage system includes, for example, a power transmitting and receiving unit that transmits and receives power between a first assembled battery having a plurality of first storage cells connected in series and a second assembled battery having a plurality of second storage cells connected in series. The power storage system includes, for example, a first power line electrically connected to a positive terminal of the first assembled battery and electrically connected to a positive terminal of the second assembled battery via the power transmitting and receiving unit. The power storage system includes, for example, a second power line electrically connected to a negative terminal of the first assembled battery and electrically connected to a negative terminal of the second assembled battery via the power transmitting and receiving unit. The power storage system includes, for example, a limiting unit disposed between the positive terminal of the first assembled battery and the first power line, or between the negative terminal of the first assembled battery and the second power line, that limits transmission and reception of power between the first assembled battery and the second assembled battery via the power transmitting and receiving unit. The power storage system includes, for example, a positive terminal of the first assembled battery, a limiting unit, and a short circuit that connects the negative terminal of the first assembled battery in series. The power storage system includes, for example, a switching unit that opens and closes the short circuit. In the above control device, for example, the first assembled battery and the second assembled battery are connected in series. In the above control device, for example, the power transmitting and receiving unit transmits and receives power between the first assembled battery and the second assembled battery via a first power line and a second power line. In the above control device, for example, the limiting unit limits transmission and reception of power between the first assembled battery and the second assembled battery via the power transmitting and receiving unit when the short circuit is closed.

[0012] The control device includes, for example, a detection unit that detects an abnormality related to power transmission or reception of the power transmitting and receiving unit. The control device includes, for example, a switching control unit that controls the opening and closing operation of the switching unit. In the control device, the switching control unit controls the opening and closing operation of the switching unit so that, for example, (i) when the detection unit does not detect an abnormality in the power transmitting and receiving unit, the switching unit opens the short circuit, and (ii) when the detection unit detects an abnormality in the power transmitting and receiving unit, the switching unit closes the short circuit.

[0013] In the above control device, the detection unit may detect an abnormality in the power transmitting and receiving unit when (i) the direction of current in at least one of the first power line, the second power line, and the power transmitting and receiving unit differs from a predetermined direction, (ii) the magnitude of current flowing from the first power line to the first assembled battery is greater than a predetermined value, (iii) the magnitude of current flowing from the first assembled battery to the second power line is greater than a predetermined value, or (iv) the operation of the power transmitting and receiving unit differs from the predetermined operation.

[0014] The above summary of the invention does not list all of the necessary features of the present invention, and subcombinations of these features may also constitute inventions. [Brief explanation of the drawings]

[0015] [Figure 1] 1 shows an example of a system configuration of a battery pack 100. [Figure 2] 2 shows an example of the internal configuration of a battery module 112. [Figure 3] 2 shows an example of the internal configuration of a battery module 114. [Figure 4] 2 shows an example of the internal configuration of the balance correction section 220. [Figure 5] 10 shows an example of the internal configuration of the balance correction circuit 432. [Figure 6] An example of the internal configuration of a DC-DC converter 330 is shown schematically. [Figure 7] 1 shows an example of the internal configuration of the system control unit 130. [Figure 8] 10A and 10B show an example of a control operation performed by the system control unit 130. [Figure 9] 10 is a schematic diagram illustrating another example of the internal configuration of the battery module 112. [Figure 10] 10 is a schematic diagram illustrating another example of the internal configuration of the battery module 112. [Figure 11] 10 shows another example of the internal configuration of the DC-DC converter 330. [Figure 12] 12 shows an example of the circuit configuration of the overcurrent protection circuit 1232. [Figure 13] 12 shows an example of the voltage-current characteristics of the overcurrent protection circuit 1232. [Figure 14] 14 shows an example of the circuit configuration of the overcurrent protection circuit 1432. [Figure 15] 14 shows an example of a voltage-current characteristic of the overcurrent protection circuit 1432. [Figure 16] 16 shows an example of the circuit configuration of the overcurrent protection circuit 1632. [Figure 17] 16 shows an example of the voltage-current characteristics of the overcurrent protection circuit 1632. [Figure 18] 18 shows an example of the circuit configuration of the overcurrent protection circuit 1832. [Figure 19] 18A and 18B show schematic diagrams of an example of the voltage-current characteristics of the overcurrent protection circuit 1832. [Figure 20] 2 shows an example of the internal configuration of a current control circuit 2030. [Figure 21] 2 shows an example of a voltage-current characteristic of the current control circuit 2030. [Figure 22] 2 shows an example of the system configuration of an electric vehicle 2200. DETAILED DESCRIPTION OF THE INVENTION

[0016] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention. Not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention. Furthermore, the embodiments will be described with reference to the drawings, but in the description of the drawings, the same reference numerals may be used to designate the same or similar parts, and redundant description may be omitted.

[0017] [Battery Pack 100 Overview] FIG. 1 schematically illustrates an example of a system configuration of a battery pack 100. In this embodiment, the battery pack 100 supplies power to an external device (sometimes referred to as a load) that uses the power. The above operation may be referred to as discharging the battery pack 100. In this embodiment, the battery pack 100 stores power supplied from the external device. The above operation may be referred to as charging the battery pack 100. For example, the battery pack 100 stores regenerated power from the load. The battery pack 100 may also store power supplied from a charging device.

[0018] In this embodiment, the battery pack 100 includes a terminal 102, a terminal 104, a battery module 112, a battery module 114, a battery module 116, a system control unit 130, and a power transmission bus 140. In this embodiment, the power transmission bus 140 includes a low-potential bus 142 and a high-potential bus 144.

[0019] In this embodiment, the terminal 102, the terminal 104, the battery module 112, the battery module 114, and the battery module 116 are connected in series. Furthermore, in this embodiment, at least two of the battery module 112, the battery module 114, and the battery module 116 transmit and receive power to each other via the power transmission bus 140. This allows the voltages or SOC (State of Charge) between the battery module 112, the battery module 114, and the battery module 116 to be equalized. The SOC is an index representing the charge / discharge state, and is defined, for example, with a fully charged state being 100% and a fully discharged state being 0%.

[0020] However, if an abnormality occurs in the function or operation of transmitting and receiving power via the power transmission bus 140 and the abnormality is left unattended for a long period of time, the voltage or SOC variation between the battery modules may become large. In many cases, the battery modules are equipped with a protection circuit to protect the battery modules from overcharging or overdischarging, which may damage the battery modules. However, if the abnormality is left unattended for an even longer period of time, the battery modules may deteriorate due to overcharging or overdischarging.

[0021] According to this embodiment, if an abnormality occurs in the function or operation of transmitting and receiving power via the power transmission bus 140, the amount of power transmitted and received via the power transmission bus 140 is limited. Specifically, the function or operation of transmitting and receiving power via the power transmission bus 140 is stopped, or the amount of power transmitted and received via the power transmission bus 140 is reduced. This prevents the voltage or SOC from increasing between the battery modules. Also, damage or deterioration of the battery modules is prevented.

[0022] As described above, in this embodiment, the terminal 102, the terminal 104, the battery module 112, the battery module 114, and the battery module 116 are connected in series. Therefore, even if the amount of power transmitted and received via the power transmission bus 140 is limited, the battery pack 100 can transmit and receive power to and from an external device.

[0023] [Overview of Battery Pack 100 Components] In this embodiment, the terminal 102 and the terminal 104 electrically connect an external device to the battery pack 100. In this embodiment, the terminal 102 is a negative terminal of the battery pack 100, and the terminal 104 is a positive terminal of the battery pack 100.

[0024] Here, "electrically connected" does not necessarily mean that the first element and the second element are directly connected. A conductive third element may be interposed between the first element and the second element. Furthermore, "electrically connected" does not necessarily mean that the first element and the second element are physically connected. For example, the input winding and the output winding of a transformer are not physically connected but are electrically connected.

[0025] Furthermore, the term "electrically connected" is not limited to cases where the first element and the second element are actually electrically connected. For example, when the first element and the second element are respectively disposed on two detachable members, and the first element and the second element are electrically connected when the two members are connected, the term "electrically connected" may be used.

[0026] Note that "connected in series" means that a first element and a second element are electrically connected in series. Furthermore, unless otherwise specified, the "voltage difference" between storage cells means the value obtained by comparing the voltages of two storage cells (sometimes referred to as terminal voltage) and subtracting the voltage of the storage cell with the lower voltage from the voltage of the storage cell with the higher voltage.

[0027] In this embodiment, at least one of battery module 112, battery module 114, and battery module 116 includes a plurality of storage cells connected in series. Each of battery module 112, battery module 114, and battery module 116 may also include a plurality of storage cells connected in series. At least one of battery module 112, battery module 114, and battery module 116 may further include one or more storage cells connected in parallel to the plurality of storage cells connected in series included in each module.

[0028] In this embodiment, at least one of the battery modules 112, 114, and 116 may include a device or element that manages the charging and discharging of the multiple storage cells included in each module. Each of the battery modules 112, 114, and 116 may include a device or element that manages the charging and discharging of the multiple storage cells included in each module. Each of the battery modules 112, 114, and 116 may include (i) multiple storage cells connected in series, and (ii) a device or element that manages the charging and discharging of the multiple storage cells. (i) the multiple storage cells connected in series, and (ii) the device or element that manages the charging and discharging of the multiple storage cells may be physically arranged in the same housing.

[0029] In this embodiment, a plurality of storage cells included in battery module 112, a plurality of storage cells included in battery module 114, and a plurality of storage cells included in battery module 116 are connected in series. In this embodiment, a plurality of storage cells included in battery module 112, a plurality of storage cells included in battery module 114, and a plurality of storage cells included in battery module 116 are connected in series so that battery module 112 is on the low potential side and battery module 116 is on the high potential side.

[0030] In this embodiment, the system control unit 130 controls the battery pack 100. For example, the system control unit 130 controls the voltage or SOC equalization operation among a plurality of battery modules. The system control unit 130 may also control the voltage or SOC equalization operation among a plurality of power storage cells.

[0031] The system control unit 130 may manage the state of the battery pack 100. For example, the system control unit 130 manages at least one of the voltages and SOCs of the battery module 112, the battery module 114, and the battery module 116. The system control unit 130 may manage variations in at least one of the voltages and SOCs among the battery module 112, the battery module 114, and the battery module 116.

[0032] The system control unit 130 may control the battery pack 100 so that variations in at least one of the voltage and the SOC among the battery modules 112, 114, and 116 satisfy a predetermined condition. Examples of the predetermined condition include a condition that the variations are smaller than a predetermined threshold, a condition that the variations are within a predetermined range, and the like. The system control unit 130 may manage the variations by controlling the operation of transmitting and receiving power via the power transmission bus 140 (sometimes referred to as an equalization operation between the battery modules).

[0033] The system control unit 130 may detect an abnormality in the battery pack 100. For example, the system control unit 130 detects an abnormality related to the equalization operation between the battery modules. When an abnormality related to the equalization operation between the battery modules is detected, for example, the system control unit 130 restricts the transmission and reception of power between the multiple battery modules via the power transmission bus 140. This suppresses the increase in the variation in voltage or SOC between the battery modules. Also, damage or deterioration of the battery modules is suppressed. Details of the system control unit 130 will be described later.

[0034] The system control unit 130 or each unit of the system control unit 130 may be configured with analog circuits, digital circuits, or a combination of analog and digital circuits. The system control unit 130 may be realized by hardware, software, or a combination of hardware and software.

[0035] When at least some of the components constituting the system control unit 130 are realized by software, the components realized by the software may be realized by starting software or a program that defines the operation of the components in an information processing device with a general configuration. The information processing device with the general configuration described above may include a data processing device having a processor, ROM, RAM, a communication interface, etc., an input device, an output device, and a storage device (including an external storage device).

[0036] In this embodiment, the power transmission bus 140 transmits power between any of the battery modules. If it is not necessary to transmit power between any of the battery modules, the low potential bus 142 and the high potential bus 144 may be electrically insulated. If it is necessary to transmit power between any of the battery modules, the low potential bus 142 and the high potential bus 144 may be electrically connected. The timing of transmitting power between any of the battery modules is determined by, for example, the system control unit 130.

[0037] In this embodiment, the low potential bus 142 is electrically connected to the negative terminals of the battery modules 112, 114, and 116. In this embodiment, the high potential bus 144 is electrically connected to the positive terminals of the battery modules 112, 114, and 116. The connections between the low potential bus 142 and the high potential bus 144 and the respective battery modules will be described in detail below.

[0038] The battery pack 100 may be an example of a power storage system. The battery module 112 may be an example of a first assembled battery. The battery module 114 may be an example of a second assembled battery. The battery module 116 may be an example of a second assembled battery. The system control unit 130 may be an example of a detection unit, a switching control unit, or a control device. The low potential bus 142 may be an example of a second power line. The high potential bus 144 may be an example of a first power line.

[0039] The transmission and reception of power via the power transmission bus 140 may be an example of the transmission and reception of power via a power transmitting and receiving unit. An abnormality related to the equalization operation between battery modules may be an example of an abnormality related to the power transmission or reception of the power transmitting and receiving unit.

[0040] [An example of another embodiment] In the present embodiment, for the purpose of simplifying the description, an example of the battery pack 100 has been described using an example in which the battery pack 100 has three battery modules. However, the battery pack 100 is not limited to the present embodiment.

[0041] In other embodiments, the battery pack 100 may include two battery modules. For example, the battery pack 100 includes the battery module 112 and the battery module 114 or the battery module 116.

[0042] In yet other embodiments, battery pack 100 may have four or more battery modules. For example, battery pack 100 may include a single battery module 112, two or more battery modules 114, and one or more battery modules 116. Battery pack 100 may also include a single battery module 112, one or more battery modules 114, and two or more battery modules 116.

[0043] 2 schematically illustrates an example of the internal configuration of the battery module 112. In this embodiment, the battery module 112 includes a terminal 202, a terminal 204, a battery pack 210, a balance correction unit 220, a protection unit 230, a terminal 242, and a terminal 244. In this embodiment, the battery module 112 includes an abnormal operation protection element 252 and a switching element 254. According to this embodiment, the terminal 204, the abnormal operation protection element 252, the switching element 254, and the terminal 202 form a circuit 260.

[0044] In this embodiment, the terminal 202 is electrically connected to the terminal 102. The terminal 202 is also electrically connected to the negative terminal of the battery pack 210. In this embodiment, the terminal 204 is electrically connected to the negative terminal of the battery module 114. As described above, in this embodiment, the terminal 102, the battery module 112, the battery module 114, the battery module 116, and the terminal 104 are connected in series. As a result, the terminal 204 is electrically connected to the terminal 104.

[0045] In this embodiment, the battery module 112 transmits and receives power to and from an external device via the terminals 102 and 104 and the terminals 202 and 204. The battery module 112 also transmits and receives power to and from the power transmission bus 140 via the terminals 242 and 242.

[0046] In this embodiment, the battery pack 210 includes a plurality of power storage cells. In this embodiment, one end on the negative electrode side of the battery pack 210 (sometimes referred to as a negative terminal) is electrically connected to the terminal 202, and one end on the positive electrode side of the battery pack 210 (sometimes referred to as a positive terminal) is electrically connected to the terminal 204.

[0047] The storage cells constituting the battery pack 210 may be secondary batteries or capacitors. Examples of types of secondary batteries include lithium batteries, lithium ion batteries, lithium sulfur batteries, sodium sulfur batteries, lead batteries, nickel-metal hydride batteries, nickel-cadmium batteries, redox flow batteries, and metal-air batteries. The type of lithium ion battery is not particularly limited. Examples of types of lithium ion batteries include iron phosphate, manganese, cobalt, nickel, and ternary batteries.

[0048] The power storage cells constituting the battery pack 210 may further include a plurality of power storage cells. In one embodiment, a single power storage cell includes a plurality of power storage cells connected in series. In another embodiment, a single power storage cell includes a plurality of power storage cells connected in parallel. In yet another embodiment, a single power storage cell includes a plurality of power storage cells connected in a matrix.

[0049] In this embodiment, the balance correction unit 220 equalizes the voltages or SOCs of the multiple storage cells included in the assembled battery 210. In one embodiment, the balance correction unit 220 equalizes the voltages or SOCs of any two storage cells included in the assembled battery 210 by transferring charge between the two storage cells. In another embodiment, the balance correction unit 220 equalizes the voltages or SOCs of any two storage cells included in the assembled battery 210 by discharging one of the two storage cells.

[0050] The balance correction unit 220 may transmit and receive information to and from the system control unit 130. For example, the balance correction unit 220 transmits a signal 22 indicating the state of the battery module 112 to the system control unit 130. Examples of the state of the battery module include the operating state of the battery module, the voltage or SOC of the battery module, the magnitude and / or direction of the current flowing through the battery module, the voltage or SOC of each of the multiple storage cells included in the assembled battery 210 of the battery module, and the operating state of the balance correction unit 220. Examples of the operating state of the battery module include charging, discharging, and stopped. Examples of the operating state of the balance correction unit 220 include operating and stopped.

[0051] The balance correction unit 220 may receive a signal 24 for controlling the operation of the battery module 112 from the system control unit 130. For example, the balance correction unit 220 receives a signal 24 for controlling an operation for equalizing the voltages or SOCs of two power storage cells (sometimes referred to as an equalization operation between power storage cells) from the system control unit 130. Examples of the signal 24 for controlling the equalization operation between power storage cells include a signal for enabling the equalization operation between power storage cells and a signal for disabling the equalization operation between power storage cells.

[0052] The balance correction unit 220 may be configured to be able to perform the equalization operation between the power storage cells without receiving the signal 24 from the system control unit 130. For example, the balance correction unit 220 is configured to be able to detect a difference in voltage or SOC between the two power storage cells using a detection circuit disposed therein, and to transfer charges between the two power storage cells based on the difference.

[0053] The protection unit 230 protects the battery pack 210 from at least one of overcurrent, overvoltage, overcharge, and overdischarge. The specific circuit configuration of the protection unit 230 is not particularly limited, and the protection unit 230 may include a known overcurrent protection circuit, a known overvoltage protection circuit, a known overcharge protection circuit, or a known overdischarge protection circuit. For example, a known overcurrent / overvoltage protection circuit such as that disclosed in Japanese Patent Application Laid-Open No. 2009-183141 can be used as the protection unit 230.

[0054] In one embodiment, the protection unit 230 performs an operation to protect the battery pack 210 based on an external signal 26. The protection unit 230 may receive the signal 26 from the system control unit 130 or from the balance correction unit 220. In another embodiment, the protection unit 230 performs an operation to protect the battery pack 210 based on outputs of various detection circuits arranged inside the protection unit 230. In this case, the protection unit 230 does not need to receive the signal 26 from an external unit. Alternatively, the signal 26 may be a signal from the various detection circuits arranged inside the protection unit 230.

[0055] 2, the arrangement of the protection unit 230 is described by taking as an example a case where the protection unit 230 includes an element arranged in series between the terminal 242 and / or the terminal 244 and the battery pack 210. However, the protection unit 230 is not limited to this embodiment. In other embodiments, the protection unit 230 includes an element arranged in series between the terminal 202 and / or the terminal 204 and the battery pack 210.

[0056] In one embodiment, the protection unit 230 controls the operation of a switching element (not shown) or a current limiting element having a reset function or a recovery function that is arranged in series between the terminal 202 and / or the terminal 204 and the battery pack 210, based on the output of at least one of a circuit (not shown) for detecting a low voltage of the battery pack 210, a circuit (not shown) for detecting an overvoltage of the battery pack 210, and a circuit (not shown) for detecting an overcurrent of the battery pack 210. For example, when at least one of a low voltage, an overvoltage, and an overcurrent is detected, the protection unit 230 turns off the switching element or the current limiting element.

[0057] In another embodiment, the protection unit 230 controls the operation of a switching element (not shown) or a current limiting element (not shown) having a reset function or a recovery function that is arranged in series between the terminal 242 and / or the terminal 244 and the battery pack 210, based on the output of at least one of a circuit (not shown) for detecting a low voltage of the battery pack 210, a circuit (not shown) for detecting an overvoltage of the battery pack 210, and a circuit (not shown) for detecting an overcurrent of the battery pack 210. For example, when at least one of a low voltage, an overvoltage, and an overcurrent is detected, the protection unit 230 turns off the switching element or the current limiting element.

[0058] In this embodiment, the terminal 242 is electrically connected to the low potential bus 140. The terminal 242 is also electrically connected to the negative terminal of the battery pack 210. In this embodiment, the terminal 244 is electrically connected to the high potential bus 140. The terminal 244 is also electrically connected to the positive terminal of the battery pack 210. In this embodiment, the positive terminal and the negative terminal of the battery pack 210 of the battery module 112 are physically connected to the power transmission bus 140. As a result, the positive terminal and the negative terminal of the battery pack 210 of the battery module 112 are always electrically connected to the power transmission bus 140.

[0059] According to this embodiment, the battery pack 210 of the battery module 112 can transmit and receive power to and from at least one of the other battery modules via the terminals 242 and 244 and the power transmission bus 140. According to this embodiment, the terminals 242 and 244 (i) transmit power from the battery pack 210 to at least one of the battery modules 114 and 116, or (ii) receive power supplied to the cells of the battery pack 210 from at least one of the battery modules 114 and 116, for example, without disconnecting or switching an electrical connection between (a) the battery pack 210 and (b-1) a load that uses the power of the battery pack 210 or (b-2) a charging device that charges the battery pack 210.

[0060] In this embodiment, the abnormal operation protection element 252 protects the battery module 112 from an abnormality related to power transmission or reception via the power transmission bus 140. For example, the abnormal operation protection element 252 protects the assembled battery 210 from an abnormality related to power transmission or reception via the power transmission bus 140. This protects the assembled battery 210 from at least one of overcurrent, overvoltage, overcharge, and overdischarge, for example.

[0061] Examples of the abnormal operation protection element 252 include at least one of a fuse, an electronic fuse (sometimes referred to as an E-fuse), a PTC (Positive Temperature Coefficient) thermistor, and a switching element. The fuse may have a reset function or a reset function, or may not have a reset function or a reset function. The electronic fuse can achieve the overcurrent cut-off function of a conventional glass tube fuse or a PTC thermistor by using one or more semiconductor switches. The electronic fuse may further have not only the overcurrent protection function, but also at least one of an overvoltage protection function, an undervoltage protection function, and a thermal shutdown function.

[0062] More specifically, in this embodiment, the abnormal operation protection element 252 is disposed between the positive terminal or terminal 204 of the battery pack 210 and the high potential bus 144 or terminal 244. The abnormal operation protection element 252 also restricts power transmission and reception via the power transmission bus 140 between the battery module 112 and the battery module 114 or the battery module 116.

[0063] In one embodiment, the abnormal operation protection element 252 limits power transmission and reception via the power transmission bus 140 by reducing the current flowing from the battery module 114 or the battery module 116 to the battery module 112 via the high-potential bus 144. In another embodiment, the abnormal operation protection element 252 limits power transmission and reception via the power transmission bus 140 by blocking the current flowing from the battery module 114 or the battery module 116 to the battery module 112 via the high-potential bus 144.

[0064] In this embodiment, the abnormal operation protection element 252 constitutes part of the circuit 260. As described above, the circuit 260 is configured so that current flows from the positive terminal of the battery pack 210, through the abnormal operation protection element 252 and the switching element 254, and back to the negative terminal of the battery pack 210. The circuit 260 opens and closes depending on the operation of the switching element 254. The operation of the switching element 254 is controlled by, for example, a signal 28 from the system control unit 130.

[0065] According to this embodiment, when the switching element 254 is turned on, the circuit 260 is short-circuited, and the abnormal operation protection element 252 restricts the transmission and reception of power via the power transmission bus 140. On the other hand, when the switching element 254 is turned off, the above restriction may be lifted depending on the abnormal operation protection element 252. For example, if the abnormal operation protection element 252 has a reset function or a recovery function, the above restriction is lifted when the switching element 254 is turned off.

[0066] The abnormal operation protection element 252 may limit transmission and reception of power via the power transmission bus 140 when an abnormality occurs in power transmission or reception via the power transmission bus 140. The abnormal operation protection element 252 may limit transmission and reception of power via the power transmission bus 140 when an abnormality in power transmission or reception via the power transmission bus 140 is detected.

[0067] In one embodiment, if the direction of at least one of the current flowing through the low-potential bus 142, the current flowing through the high-potential bus 144, and the output current from the battery module 114 or the battery module 116 to the power transmission bus 140 differs from a predetermined direction, it is determined that an abnormality has occurred in the transmission or reception of power via the power transmission bus 140. This detects the abnormality.

[0068] As will be described later, the battery module 114 or the battery module 116 transmits and receives power to and from an external device via the terminals 102 and 104. The battery module 114 or the battery module 116 also includes a DC-DC converter, and transmits and receives power to and from the power transmission bus 140 via the DC-DC converter. The direction of the output current is opposite when a current flows from the battery module 114 or the battery module 116 to the power transmission bus 140 and when a current flows from the power transmission bus 140 to the battery module 114 or the battery module 116.

[0069] In another embodiment, if the magnitude of the current flowing from the high-potential bus 144 to the battery module 112 is greater than a predetermined value, it is determined that an abnormality has occurred in the transmission or reception of power via the power transmission bus 140. This detects the abnormality.

[0070] In another embodiment, if the magnitude of the current flowing from the battery module 112 to the low-potential bus 142 is greater than a predetermined value, it is determined that an abnormality has occurred in the power transmission or reception via the power transmission bus 140. This detects the abnormality.

[0071] In still another embodiment, if the operation of the battery module 114 or the battery module 116 regarding the transmission or reception of power via the power transmission bus 140 differs from a predetermined operation, it is determined that an abnormality has occurred regarding the transmission or reception of power via the power transmission bus 140. In this way, the abnormality is detected.

[0072] An example of the predetermined operation is an operation commanded by the system control unit 130 to the battery module 114 or the battery module 116 regarding power transmission or reception via the power transmission bus 140. As a result, when the operation that the battery module 114 or the battery module 116 should currently be performing regarding power transmission or reception via the power transmission bus 140 differs from the operation that the battery module 114 or the battery module 116 is actually performing, the above-mentioned abnormality is detected.

[0073] For example, if the system control unit 130 detects an abnormality related to power transmission or reception via the power transmission bus 140, the abnormal operation protection element 252 restricts the transmission and reception of power via the power transmission bus 140. More specifically, if no such abnormality is detected, the circuit 260 is open and not short-circuited. Here, if the system control unit 130 detects the abnormality, the system control unit 130 transmits a signal 28 to the switching element 254 to close the circuit 260. Upon receiving the signal 28, the switching element 254 closes the circuit 260 in accordance with the signal 28. This shorts the circuit 260, causing a large current to flow through the abnormal operation protection element 252. According to this embodiment, if the magnitude of the current flowing through the abnormal operation protection element 252 exceeds a predetermined value, the resistance of the abnormal operation protection element 252 increases or the abnormal operation protection element 252 shuts off the circuit 260. As a result, the transmission and reception of power via the power transmission bus 140 is restricted.

[0074] In this embodiment, the switching element 254 opens and closes the circuit 260. For example, the switching element 254 opens the circuit 260 when no abnormality is detected in the transmission or reception of power via the power transmission bus 140. The switching element 254 closes the circuit 260 when an abnormality is detected in the transmission or reception of power via the power transmission bus 140. In this embodiment, the switching element 254 opens and closes the circuit 260 in accordance with the signal 28 from the system control unit 130.

[0075] The type of switching element 254 is not particularly limited, but examples of the switching element 254 include a mechanical switch and a semiconductor switch. Examples of the semiconductor switch include a transistor, a thyristor, and a triac. Examples of the transistor include a bipolar transistor (BJT) and a field effect transistor (FET).

[0076] In this embodiment, circuit 260 connects terminal 204, abnormal operation protection element 252, switching element 254, and terminal 202 in series. As described above, when switching element 254 closes circuit 260, circuit 260 is shorted.

[0077] The terminal 202 of the battery module 112 may be an example of a negative terminal of the first assembled battery. The negative terminal of the assembled battery 210 of the battery module 112 may be an example of a negative terminal of the first assembled battery. The terminal 204 of the battery module 112 may be an example of a positive terminal of the first assembled battery. The positive terminal of the assembled battery 210 of the battery module 112 may be an example of a positive terminal of the first assembled battery. The assembled battery 210 of the battery module 112 may be an example of a first assembled battery. The multiple storage cells included in the assembled battery 210 of the battery module 112 may be an example of a multiple first storage cells. The balance correction unit 220 of the battery module 112 may be an example of a first equalization unit. The abnormal operation protection element 252 may be an example of a limiting unit. The switching element 254 may be an example of an opening / closing unit. The circuit 260 may be an example of a short circuit.

[0078] The direction of at least one of the current flowing through the low-potential bus 142, the current flowing through the high-potential bus 144, and the output current of the battery module 114 or the battery module 116 may be an example of the direction of current in at least one of the first power line, the second power line, and the power transmitting and receiving unit. The current flowing from the battery module 114 or the battery module 116 to the battery module 112 via the high-potential bus 144 may be an example of a current flowing from the second assembled battery to the first assembled battery via the power transmitting and receiving unit and the first power line. The operation of the battery module 114 or the battery module 116 related to transmitting or receiving power via the power transmission bus 140 may be an example of the operation of the power transmitting and receiving unit.

[0079] [An example of another embodiment] In this embodiment, an example of the battery module 112 has been described, taking as an example a case where the abnormal operation protection element 252 is arranged between the positive terminal or terminal 204 of the battery pack 210 and the high potential bus 144 or terminal 244. However, the battery module 112 is not limited to this embodiment. In other embodiments, the abnormal operation protection element 252 may be arranged between the negative terminal or terminal 202 of the battery pack 210 and the low potential bus 142 or terminal 242.

[0080] 3 schematically illustrates an example of the internal configuration of the battery module 114. In this embodiment, the battery module 114 includes a terminal 202, a terminal 204, a battery pack 210, a balance correction unit 220, a protection unit 230, a DC-DC converter 330, a terminal 242, and a terminal 244. The battery module 116 may also have the same internal configuration as the battery module 114.

[0081] In this embodiment, the battery module 114 differs from the battery module 112 in that (i) it includes a DC-DC converter 330, (ii) the DC-DC converter 330 has a terminal 242 and a terminal 244, (iii) the terminal 242 is not physically connected to the negative terminal of the battery pack 210 or the terminal 202, (iv) the terminal 244 is not physically connected to the positive terminal of the battery pack 210 or the terminal 204, and (v) it does not include an abnormal operation protection element 252 or a switching element 254. Other than the above differences, the battery module 114 may have the same configuration as the battery module 112.

[0082] In this embodiment, the negative electrode end or terminal 202 of the battery pack 210 and the low potential bus 142 or terminal 242 are electrically connected via a DC-DC converter 330. The positive electrode end or terminal 204 of the battery pack 210 and the high potential bus 144 or terminal 244 are electrically connected via the DC-DC converter 330.

[0083] In this embodiment, the DC-DC converter 330 transmits and receives power between the battery pack 210 of the battery module 114 and at least one of the other battery modules via the power transmission bus 140. For example, the DC-DC converter 330 (i) transmits power from the battery pack 210 to at least one of the battery modules 112 and 116, or (ii) receives power supplied to the cells of the battery pack 210 from at least one of the battery modules 112 and 116, without disconnecting or switching the electrical connection between (a) the battery pack 210 and (b-1) a load that uses the power of the battery pack 210 or (b-2) a charging device that charges the battery pack 210. The DC-DC converter 330 may adjust the voltage of the transmitted or received power to any value.

[0084] In this embodiment, the DC-DC converter 330 may start power transmission or reception in response to receiving a signal to start power transmission or reception. The DC-DC converter 330 may stop power transmission or reception in response to receiving a signal to stop power transmission or reception. For example, the DC-DC converter 330 starts power transmission or reception or stops power transmission or reception based on a signal 32 from the system control unit 130. The signal 32 may be a signal including information indicating the start of an operation and information indicating which of the power transmission operation and the power receiving operation should be performed. The signal 32 may be a signal indicating the start of a power transmission operation. The signal 32 may be a signal indicating the start of a power receiving operation. The signal 32 may be information indicating the stop of a current operation.

[0085] The details of the DC-DC converter 330 are not particularly limited, but the DC-DC converter 330 may be an isolated DC-DC converter 330. The DC-DC converter 330 may be a bidirectional DC-DC converter. The battery module 114 may include multiple DC-DC converters 330.

[0086] The DC-DC converter 330 may be a forward DC-DC converter or a flyback DC-DC converter. In the battery pack 100, the rated voltages of the battery modules 112, 114, and 116 may differ. Therefore, it is preferable that the DC-DC converter 330 be a flyback DC-DC converter that can handle a wide range of voltages.

[0087] The DC-DC converter 330 may be a self-excited DC-DC converter or a separately excited DC-DC converter. The DC-DC converter 330 may be an asynchronous rectification DC-DC converter or a synchronous rectification DC-DC converter. There are no particular limitations on the control method for the DC-DC converter 330, but it is preferable to implement constant current control. An embodiment of the DC-DC converter 330 will be described in detail below.

[0088] The terminal 202 of the battery module 114 or the battery module 116 may be an example of a negative terminal of the second assembled battery. The negative terminal of the assembled battery 210 of the battery module 114 or the battery module 116 may be an example of a negative terminal of the second assembled battery. The terminal 204 of the battery module 114 or the battery module 116 may be an example of a positive terminal of the second assembled battery. The positive terminal of the assembled battery 210 of the battery module 114 or the battery module 116 may be an example of a positive terminal of the second assembled battery. The assembled battery 210 of the battery module 114 or the battery module 116 may be an example of a second assembled battery. The multiple storage cells included in the assembled battery 210 of the battery module 114 or the battery module 116 may be an example of a multiple number of second storage cells. The balance correction unit 220 of the battery module 114 or the battery module 116 may be an example of a second equalization unit. The DC-DC converter 330 may be an example of a power transmitting and receiving unit.

[0089] [An example of another embodiment] 2 does not include a DC-DC converter 330. However, the battery module 112 is not limited to the above embodiment. The battery module 112 may have a configuration similar to that of the battery module 114. It is preferable that at least one of the battery modules 112, 114, and 116 includes a bidirectional DC-DC converter.

[0090] 4 schematically illustrates an example of the internal configuration of the balance correction unit 220. FIG. 4 illustrates an example of the internal configuration of the balance correction unit 220 together with the terminals 202, 204, and the assembled battery 210. In this embodiment, the assembled battery 210 is configured with a plurality of series-connected power storage cells, including a power storage cell 412, a power storage cell 414, a power storage cell 416, and a power storage cell 418. In this embodiment, the balance correction unit 220 includes a plurality of power storage circuits, including a power storage circuit 432, a power storage circuit 434, and a power storage circuit 436. In this embodiment, the balance correction unit 220 includes a module control unit 490.

[0091] In this embodiment, the balance correction circuit 432 equalizes the voltages of the power storage cell 412 and the power storage cell 414. In this embodiment, the balance correction circuit 432 is electrically connected to one end (sometimes referred to as the positive electrode side) of the power storage cell 414 on the terminal 204 side. The balance correction circuit 432 is electrically connected to a connection point 443 between one end (sometimes referred to as the negative electrode side) of the power storage cell 414 on the terminal 202 side and the positive electrode side of the power storage cell 412. The balance correction circuit 432 is electrically connected to the negative electrode side of the power storage cell 412.

[0092] In this embodiment, a case will be described in which the balance correction circuit 432 equalizes the voltages of two adjacent storage cells. However, the balance correction circuit 432 is not limited to this embodiment. In other embodiments, the balance correction circuit 432 may equalize the voltages of any two storage cells among three or more storage cells connected in series.

[0093] In this embodiment, the balance correction circuit 434 equalizes the voltages of the power storage cell 414 and the power storage cell 416. The balance correction circuit 434 is electrically connected to a connection point 443, a connection point 445 between the positive electrode side of the power storage cell 414 and the negative electrode side of the power storage cell 416, and a connection point 447 between the positive electrode side of the power storage cell 416 and the negative electrode side of the power storage cell 418. The balance correction circuit 434 may have a similar configuration to the balance correction circuit 432.

[0094] In this embodiment, the balance correction circuit 436 equalizes the voltages of the power storage cell 416 and the power storage cell 418. The balance correction circuit 436 is electrically connected to the connection point 445, the connection point 447, and the positive electrode side of the power storage cell 418. The balance correction circuit 436 may have a configuration similar to that of the balance correction circuit 432.

[0095] In this embodiment, the module control unit 490 controls the operation of the battery module in which the module control unit 490 is mounted. The module control unit 490 may be driven using the power of the assembled battery 210.

[0096] For example, the module control unit 490 controls the balance correction circuit 432, the balance correction circuit 434, and / or the balance correction circuit 436. In one embodiment, the module control unit 490 determines the direction of charge transfer. For example, the module control unit 490 determines the direction of charge transfer based on the voltages or SOCs of the two energy storage cells that are the targets of the cell equalization operation. The module control unit 490 may send a signal including information indicating the direction of charge transfer to the corresponding balance correction circuit. In another embodiment, the module control unit 490 determines whether to activate each balance correction circuit. The module control unit 490 also determines whether to deactivate each balance correction circuit. The module control unit 490 may send a signal including information indicating the activation or deactivation of each balance correction circuit to the corresponding balance correction circuit.

[0097] In this embodiment, the module control unit 490 collects information related to the state of the assembled battery 210 and / or the balance correction unit 220. The module control unit 490 may transmit the information related to the state of the assembled battery 210 and / or the balance correction unit 220 to the system control unit 130. For example, the module control unit 490 transmits information indicating the voltage of each of the multiple storage cells to the system control unit 130. For example, the module control unit 490 transmits information indicating the inter-terminal voltage of the assembled battery 210 to the system control unit 130. For example, the module control unit 490 transmits information indicating the operating status of each balance correction circuit to the system control unit 130.

[0098] The power storage cell 412 may be an example of a first power storage cell or a second power storage cell. The power storage cell 414 may be an example of a first power storage cell or a second power storage cell. The power storage cell 416 may be an example of a first power storage cell or a second power storage cell. The power storage cell 418 may be an example of a first power storage cell or a second power storage cell. The balance correction circuit 432 may be an example of a first equalization unit or a second equalization unit. The balance correction circuit 434 may be an example of a first equalization unit or a second equalization unit. The balance correction circuit 436 may be an example of a first equalization unit or a second equalization unit.

[0099] 5 schematically illustrates an example of the internal configuration of the balance correction circuit 432. Also illustrated in FIG. 5 is an example of the internal configuration of the balance correction circuit 432, including the power storage cell 412, the power storage cell 414, and the module control unit 490. The balance correction circuit 434 and the balance correction circuit 436 may also have the same internal configuration as the balance correction circuit 432.

[0100] In this embodiment, the balance correction circuit 432 includes an inductor 550, a switching element 552, a switching element 554, and an equalization control unit 570. The balance correction circuit 432 may include a diode 562 and a diode 564. The balance correction circuit 432 may include a voltage monitoring unit 580. The voltage monitoring unit 580 includes, for example, a voltage detection unit 582, a voltage detection unit 584, and a difference detection unit 586.

[0101] The equalization control unit 570, and the switching elements 554 and 552 may be arranged on the same physical substrate or on different physical substrates. The equalization control unit 570 and the module control unit 490 may be formed on the same physical substrate or on different physical substrates.

[0102] In this embodiment, a case will be described in which, as a current detection unit for detecting the inductor current flowing through the inductor 550, (i) a resistor provided at an appropriate position in a first circuit including the energy storage cell 414, the inductor 550, and the switching element 554 or the diode 564, and (ii) a resistor provided at an appropriate position in a second circuit including the energy storage cell 412, the inductor 550, and the switching element 552 or the diode 562 are used. The resistors may be shunt resistors.

[0103] However, the current detection unit is not limited to this embodiment. In other embodiments, at least one of the internal resistance of switching element 552 and the internal resistance of switching element 554 may be used as the current detection unit. In still other embodiments, the current detection unit may be an ammeter that detects the current flowing through inductor 550 and transmits a signal including information indicating the current value of inductor 550 to equalization control unit 570.

[0104] In this embodiment, the balance correction circuit 432 is electrically connected to (i) the positive electrode side of the power storage cell 414, (ii) a connection point 443 between the negative electrode side of the power storage cell 414 and the positive electrode side of the power storage cell 412, and (iii) the negative electrode side of the power storage cell 412. This forms a first opening and closing circuit including the power storage cell 414, the switching element 554, and the inductor 550. In addition, a second opening and closing circuit including the power storage cell 412, the inductor 550, and the switching element 552 is formed.

[0105] In this embodiment, the inductor 550 is disposed between the power storage cell 414 and the switching element 554, and is connected in series to the power storage cell 414 and the switching element 554. Thus, the inductor 550 and the switching element 554 cooperate to adjust the voltage or SOC of at least one of the power storage cell 412 and the power storage cell 414. In this embodiment, one end of the inductor 550 is electrically connected to the connection point 443. The other end of the inductor 550 is electrically connected to the connection point 545 of the switching element 552 and the switching element 554.

[0106] According to this embodiment, the switching element 552 and the switching element 554 alternately repeat an on operation and an off operation (sometimes referred to as an on-off operation), so that the inductor current I L This allows electrical energy to be exchanged between the power storage cell 412 and the power storage cell 414 via the inductor 550. As a result, the voltages of the power storage cell 412 and the power storage cell 414 can be equalized.

[0107] In this embodiment, the switching element 552 is electrically connected between the other end of the inductor 550 and the negative electrode of the power storage cell 412. The switching element 552 receives a drive signal 52 from the equalization control unit 570 and performs an on or off operation based on the drive signal 52. The operation of the switching element 552 opens or closes the second opening and closing circuit. The switching element 552 may be a semiconductor transistor such as a MOSFET.

[0108] In this embodiment, the switching element 554 is electrically connected between the other end of the inductor 550 and the positive electrode side of the power storage cell 414. The switching element 554 receives a drive signal 54 from the equalization control unit 570 and performs an on or off operation based on the drive signal 54. The operation of the switching element 554 opens or closes the first opening and closing circuit. The switching element 554 may be a semiconductor transistor such as a MOSFET.

[0109] In this embodiment, the diode 562 is electrically connected between the other end of the inductor 550 and the negative electrode of the power storage cell 412. The diode 562 is arranged in parallel with the switching element 552. When the switching element 552 is a semiconductor element such as a MOSFET, the diode 562 may be a parasitic diode formed equivalently between the source and drain of the switching element 552.

[0110] In this embodiment, the diode 562 allows current to flow in the direction from the negative electrode side of the power storage cell 412 to the other end of the inductor 550. On the other hand, the diode 562 does not allow current to flow in the direction from the other end of the inductor 550 to the negative electrode side of the power storage cell 412. In other words, current flowing from the negative electrode side of the power storage cell 412 to the positive electrode side of the power storage cell 412 can pass through the diode 562, but current flowing from the positive electrode side of the power storage cell 412 to the negative electrode side of the power storage cell 412 cannot pass through the diode 562.

[0111] In this embodiment, the diode 564 is electrically connected between the other end of the inductor 550 and the positive electrode of the power storage cell 414. The diode 564 is arranged in parallel with the switching element 554. When the switching element 554 is a semiconductor element such as a MOSFET, the diode 564 may be a parasitic diode formed equivalently between the source and drain of the switching element 554.

[0112] In this embodiment, the diode 564 allows current to flow in the direction from the other end of the inductor 550 to the positive electrode side of the power storage cell 414. On the other hand, the diode 564 does not allow current to flow in the direction from the positive electrode side of the power storage cell 414 to the other end of the inductor 550. In other words, current flowing from the negative electrode side of the power storage cell 414 to the positive electrode side of the power storage cell 414 can pass through the diode 564, but current flowing from the positive electrode side of the power storage cell 414 to the negative electrode side of the power storage cell 414 cannot pass through the diode 564.

[0113] Since the balance correction circuit 432 includes the diode 562 and the diode 564, the inductor current I flows in the first circuit or the second circuit during a period when both the switching element 552 and the switching element 554 are in an off state. L Even if the inductor current I L can continue to flow in the circuit through the diode 562 or the diode 564. This allows the balance correction circuit 432 to L In addition, the balance correction circuit 432 can effectively utilize the inductor current I L This can suppress the occurrence of surge voltage that occurs when the power is cut off.

[0114] In this embodiment, the equalization control unit 570 controls at least one of the switching element 552 and the switching element 554 to control the balance correction circuit 432. For example, the equalization control unit 570 controls at least one of the switching element 552 and the switching element 554 based on a signal 58 from the module control unit 490. The signal 58 may have a configuration similar to that of the signal transmitted from the module control unit 490 to the balance correction circuit, as described in relation to FIG.

[0115] In this embodiment, the equalization control unit 570 supplies a drive signal 52 to the switching element 552 to control the on / off operation of the switching element 552. The equalization control unit 570 also supplies a drive signal 54 to the switching element 554 to control the on / off operation of the switching element 554.

[0116] In one embodiment, the equalization control unit 570 supplies the drive signals 52 and 54 so that the switching elements 552 and 554 alternately (or complementarily) repeat on-off operations. As a result, while the balance correction circuit 432 is operating, a switching operation is repeated in which a state in which a current flows through the first circuit and a state in which a current flows through the second circuit alternately.

[0117] In another embodiment, the equalization control unit 570 supplies the drive signals 52 and 54 so that one of the switching elements 552 and 554 repeatedly switches on and off, while the other of the switching elements 552 and 554 remains off. As a result, while the balance correction circuit 432 is operating, a switching operation is repeated in which a state in which a current flows through the first circuit and a state in which a current flows through the second circuit alternately.

[0118] The equalization control unit 570 may combine the drive signal 52 and the drive signal 54 to generate various control signals used to control the balance correction circuit 432. In one embodiment, the equalization control unit 570 generates a first control signal for turning on the switching element 554 and turning off the switching element 552. In another embodiment, the equalization control unit 570 generates a second control signal for turning off the switching element 554 and turning on the switching element 552. In yet another embodiment, the equalization control unit 570 generates a third control signal for turning off the switching element 554 and turning off the switching element 552. The first control signal, the second control signal, and the third control signal may be constituted by the drive signal 52 and the drive signal 54, respectively.

[0119] For example, when the balance correction circuit 432 is in an operating state, the equalization control unit 570 controls the balance correction circuit 432 so that the balance correction circuit 432 repeats a switching operation. The equalization control unit 570 may supply the drive signals 52 and 54 to the switching elements 552 and 554 so that the balance correction circuit 432 repeats a switching operation at a predetermined cycle while the balance correction circuit 432 is in an operating state. Furthermore, for example, when the balance correction circuit 432 is in a stopped state, the equalization control unit 570 controls the balance correction circuit 432 so that the balance correction circuit 432 stops its switching operation.

[0120] The switching operation may include (i) a first operation in which the switching element 554 is operated on and the switching element 552 is operated off, and (ii) a second operation in which the switching element 554 is operated off and the switching element 552 is operated on. In addition to the first and second operations, the switching operation may include a third operation in which both the switching element 554 and the switching element 552 are operated off. The order of the first, second, and third operations may be determined arbitrarily, but it is preferable that the second operation be performed following the first operation. The switching operation may include other operations different from the first, second, and third operations described above.

[0121] In this embodiment, the voltage monitoring unit 580 monitors the voltage of at least one of the power storage cell 412 and the power storage cell 414. In this embodiment, the voltage monitoring unit 580 detects the voltage of the power storage cell 412 and the voltage of the power storage cell 414 using the voltage detection unit 582 and the voltage detection unit 584. The voltage monitoring unit 580 inputs the voltage of the power storage cell 412 and the voltage of the power storage cell 414 to the difference detection unit 586 to detect the voltage difference between the power storage cell 412 and the power storage cell 414. The voltage monitoring unit 580 generates a signal 56 indicating the detected voltage difference and transmits it to the module control unit 490. The signal 56 may include information indicating which of the voltage of the power storage cell 412 and the voltage of the power storage cell 414 is larger. The signal 56 may include information indicating the voltage of the power storage cell 412 and the voltage of the power storage cell 414.

[0122] [An example of another embodiment] In the present embodiment, the balance correction circuit 432 equalizes the voltages of the storage cells 412 and 414 using an inductor 550, a switching element 552, and a switching element 554. However, the balance correction circuit 432 is not limited to this embodiment. The balance correction circuit 432 may equalize the voltages of the storage cells 412 and 414 using a known equalization method or an equalization method developed in the future. In one embodiment, a balance correction circuit that uses a resistor to release energy from a storage cell with a higher voltage is used. In another embodiment, a balance correction circuit that uses a transformer to transfer charge is used.

[0123] 6 schematically shows an example of the internal configuration of the DC-DC converter 330. In this embodiment, the DC-DC converter 330 includes a transformer 610. In this embodiment, the DC-DC converter 330 includes a switching element 622, a diode 634, a discharge control unit 642, a current detection unit 652, and a capacitor 662. This allows the power of the battery pack 210 to be supplied to other battery modules.

[0124] In this embodiment, the DC-DC converter 330 includes a switching element 624, a diode 632, a charge control unit 644, a current detection unit 654, and a capacitor 664. This allows the assembled battery 210 to be charged using power supplied from another battery module.

[0125] In this embodiment, the transformer 610 includes two coils. The transformer 610 transfers energy from one coil to the other coil, and also transfers energy from the other coil to the one coil.

[0126] In this embodiment, one end of one coil of the transformer 610 is electrically connected to the positive terminal of the battery pack 210. The other end of the one coil of the transformer 610 is electrically connected to one end of the switching element 622. The other end of the switching element 622 is electrically connected to the negative terminal of the battery pack 210.

[0127] In this embodiment, one end of the other coil of the transformer 610 is electrically connected to the terminal 244. The other end of the other coil of the transformer 610 is electrically connected to one end of the switching element 624. The other end of the switching element 624 is electrically connected to the terminal 242.

[0128] In this embodiment, the switching element 622 performs an on-operation and an off-operation based on a signal from the discharge control unit 642. The switching element 622 may be a semiconductor transistor such as a MOSFET. In this embodiment, the switching element 624 performs an on-operation and an off-operation based on a signal from the charge control unit 644. The switching element 622 may be a semiconductor transistor such as a MOSFET.

[0129] In this embodiment, the diode 632 is electrically connected between the other end of one coil of the transformer 610 and the negative terminal of the battery pack 210. The diode 632 is arranged in parallel with the switching element 622. When the switching element 622 is a semiconductor element such as a MOSFET, the diode 632 may be a parasitic diode formed equivalently between the source and drain of the switching element 622. In this embodiment, the diode 632 passes a current in a direction from the negative terminal of the battery pack 210 to the positive terminal of the battery pack 210. On the other hand, the diode 632 does not pass a current in a direction from the positive terminal of the battery pack 210 to the negative terminal of the battery pack 210.

[0130] In this embodiment, the diode 634 is electrically connected between the other end of the other coil of the transformer 610 and the terminal 242. The diode 634 is arranged in parallel with the switching element 624. When the switching element 624 is a semiconductor element such as a MOSFET, the diode 634 may be a parasitic diode formed equivalently between the source and drain of the switching element 624. In this embodiment, the diode 634 passes a current in the direction from the terminal 242 to the terminal 244. On the other hand, the diode 634 does not pass a current in the direction from the terminal 244 to the terminal 242.

[0131] In this embodiment, the discharge control unit 642 controls the switching element 622. For example, the discharge control unit 642 generates a signal for controlling the on and off operations of the switching element 622 and transmits the generated signal to the switching element 622. The discharge control unit 642 may include a pulse width modulator. The discharge control unit 642 may generate the above signal using the pulse width modulator.

[0132] In one embodiment, the discharge control unit 642 acquires information indicating the magnitude of the current flowing through the transformer 610 from the current detection unit 652. The discharge control unit 642 may generate a signal for controlling the on and off operations of the switching element 622 based on the information indicating the magnitude of the current flowing through the transformer 610.

[0133] For example, the discharge control unit 642 generates a signal for controlling the on and off operations of the switching element 622 so that the magnitude of the current flowing through one coil of the transformer 610 satisfies a predetermined condition. The predetermined condition may be that the magnitude of the current flowing through one coil of the transformer 610 is approximately equal to the rated current value of the DC-DC converter 330.

[0134] In another embodiment, the discharge control unit 642 generates a signal for controlling the on and off operations of the switching element 622 so that the voltage between the terminals 242 and 244 satisfies a predetermined condition. Examples of the predetermined condition include a condition that the voltage between the terminals 242 and 244 is approximately equal to a predetermined value, or a condition that the voltage between the terminals 242 and 244 falls within a predetermined range.

[0135] In this embodiment, the discharge control unit 642 transmits a signal 62 including information indicating the operating status of the discharge control unit 642 to the system control unit 130. Examples of the information indicating the operating status of the discharge control unit 642 include information indicating that the discharge control unit 642 is operating, information indicating that the discharge control unit 642 is stopped, and information indicating the amount of operation. The discharge control unit 642 may be provided with a power source (not shown), and may be driven using power supplied from the battery pack 210 or power supplied from the power transmission bus 140.

[0136] In this embodiment, the charge control unit 644 controls the switching element 624. For example, the charge control unit 644 generates a signal for controlling the on and off operations of the switching element 624 and transmits the generated signal to the switching element 624. The charge control unit 644 may include a pulse width modulator. The charge control unit 644 may generate the signal using the pulse width modulator.

[0137] In one embodiment, the charging control unit 644 acquires information indicating the magnitude of the current flowing through the transformer 610 from the current detection unit 652. The charging control unit 644 may generate a signal for controlling the on and off operations of the switching element 624 based on the information indicating the magnitude of the current flowing through the transformer 610.

[0138] For example, the charging control unit 644 generates a signal for controlling the ON and OFF operations of the switching element 624 so that the magnitude of the current flowing through the other coil of the transformer 610 satisfies a predetermined condition. The predetermined condition may be that the magnitude of the current flowing through the other coil of the transformer 610 is approximately equal to the rated current value of the DC-DC converter 330.

[0139] In another embodiment, the charge control unit 644 generates a signal for controlling the on and off operations of the switching element 624 so that the voltage applied to the battery pack 210 satisfies a predetermined condition. Examples of the predetermined condition include a condition that the voltage applied to the battery pack 210 is approximately equal to a predetermined value, and a condition that the voltage applied to the battery pack 210 falls within a predetermined range.

[0140] In this embodiment, the charging control unit 644 transmits a signal 64 including information indicating the operating status of the charging control unit 644 to the system control unit 130. Examples of the information indicating the operating status of the charging control unit 644 include information indicating that the charging control unit 644 is operating, information indicating that the charging control unit 644 is stopped, and information indicating the amount of operation. The charging control unit 644 may be provided with a power source (not shown) for driving it, or may be driven using power supplied from the power transmission bus 140.

[0141] In this embodiment, the current detection unit 652 detects the current flowing through one coil of the transformer 610. The current detection unit 652 provides information indicating the magnitude of the detected current to the discharge control unit 642. In this embodiment, the current detection unit 654 detects the current flowing through the other coil of the transformer 610. The current detection unit 652 provides information indicating the magnitude of the detected current to the discharge control unit 642.

[0142] In this embodiment, one end of the capacitor 662 is electrically connected to one end of one coil of the transformer 610. The other end of the capacitor 662 is electrically connected to the other end of the switching element 622. The capacitor 662 is arranged in parallel with the assembled battery 210. In this embodiment, one end of the capacitor 664 is electrically connected to one end of the other coil of the transformer 610. The other end of the capacitor 664 is electrically connected to the other end of the switching element 624. The capacitor 664 is arranged in parallel with the assembled battery 210 of the battery module 112 via the abnormal operation protection element 252 of the battery module 112.

[0143] 7 schematically illustrates an example of the internal configuration of the system control unit 130. In this embodiment, the system control unit 130 includes a module management unit 720 and a module balance management unit 740. In this embodiment, the module management unit 720 includes a voltage management unit 722, a current management unit 724, a SOC management unit 726, and a cell balance management unit 728. In this embodiment, the module balance management unit 740 includes an instruction management unit 742, an operation management unit 744, an abnormality detection unit 746, and a protection signal output unit 748.

[0144] In this embodiment, the module management unit 720 manages the status of each of the battery modules 112, 114, and 116. For example, the module management unit 720 acquires information indicating the status of each battery module. The module management unit 720 may also acquire information indicating the status of the power storage cells arranged in each battery module.

[0145] For example, the module management unit 720 receives a signal 22 including information indicating the status of each battery module from the module control unit 490 of each battery module. The module management unit 720 and each unit thereof store the information indicating the status of each battery module in a storage device (not shown).

[0146] In this embodiment, the voltage management unit 722 manages the voltages of the battery module 112, the battery module 114, and the battery module 116. The voltage management unit 722 may manage information indicating the magnitude of the voltage of each battery module. The voltage management unit 722 may manage information indicating a time and information indicating the magnitude of the voltage at that time in association with each other. Examples of the voltage include the voltage between the terminals of the battery pack 210 and / or the potential difference between the terminals 242 and 244.

[0147] In this embodiment, the current management unit 724 manages the current flowing through the assembled battery 210 of each of the battery modules 112, 114, and 116. The current management unit 724 may manage information indicating the magnitude of the current flowing through the assembled battery 210 of each battery module. The current management unit 724 may manage information indicating the direction of the current flowing through the assembled battery 210 of each battery module. The current management unit 724 may manage information indicating a time in association with information indicating at least one of the magnitude and direction of the current at that time.

[0148] In this embodiment, the SOC management unit 726 manages the SOC of each of the assembled batteries 210 in the battery module 112, the battery module 114, and the battery module 116. The SOC management unit 726 may manage information indicating the magnitude of the SOC of each battery module. The SOC management unit 726 may manage information indicating a time and information indicating the magnitude of the SOC at that time in association with each other.

[0149] In this embodiment, the cell balancing management unit 728 manages a plurality of power storage cells included in the assembled batteries 210 of each of the battery modules 112, 114, and 116. The cell balancing management unit 728 may manage information related to the power storage cells. For example, the cell balancing management unit 728 manages information indicating the voltage or SOC of each power storage cell.

[0150] The cell balancing management unit 728 may manage the voltage or SOC of the storage cells in each battery module by controlling the equalization operation between the storage cells in each battery module. For example, the cell balancing management unit 728 generates a signal 24 for controlling the equalization operation between the storage cells in each battery module based on the voltage or SOC of each storage cell in each battery module. The cell balancing management unit 728 may transmit the signal 24 to the target battery module.

[0151] In this embodiment, the module balance management unit 740 manages the equalization operation between at least two battery modules among the battery module 112, the battery module 114, and the battery module 116. The module balance management unit 740 manages the equalization operation so that the voltages and / or SOCs of the battery module 112, the battery module 114, and the battery module 116 are substantially the same.

[0152] In this embodiment, the instruction management unit 742 manages instructions regarding the equalization operation sent from the system control unit 130 to each battery module. For example, the instruction management unit 742 generates a signal 32 for controlling the operation of the DC-DC converter 330 arranged in at least one of the battery module 114 and the battery module 116, based on the voltage and / or SOC of each battery module acquired by the voltage management unit 722 and / or the SOC management unit 726. The instruction management unit 742 transmits the signal 32 to the target battery module.

[0153] As described above, the battery module 114 and the battery module 116 transmit and receive power to and from the power transmission bus 140 via the DC-DC converter 330. The instruction management unit 742 can control the transmission and reception of power between the battery module and the power transmission bus 140 by controlling the operation of the DC-DC converter 330 disposed in the battery module.

[0154] On the other hand, the terminals 242 and 244 of the battery module 112 are physically connected to the power transmission bus 140. When the terminal voltage of the battery pack 210 is smaller than the potential difference between the terminals 242 and 244, the battery pack 210 can be charged. When the terminal voltage of the battery pack 210 is larger than the potential difference between the terminals 242 and 244, the battery pack 210 can be discharged. The command management unit 742 controls the operation of the DC-DC converter 330 arranged in the battery module 114 and / or the battery module 116 to control the potential difference between the low potential bus 142 and the high potential bus 144, thereby controlling the transmission and reception of power between the battery module 112 and the power transmission bus 140.

[0155] More specifically, the instruction management unit 742 generates a signal including, for example, at least one of (i) an instruction to cause the DC-DC converter 330 of a battery module that transmits power to the power transmission bus 140 to start a power transmission operation, and (ii) an instruction to cause the DC-DC converter 330 of a battery module that receives power from the power transmission bus 140 to start a power receiving operation. The instruction management unit 742 may generate the above signal based on the voltage or SOC of each of the multiple power storage cells that make up the assembled battery 210 of each battery module. The instruction management unit 742 may generate the above signal based on the voltage or SOC of each of the assembled battery 210 of each battery module.

[0156] The instruction management unit 742 generates a signal including, for example, at least one of (i) an instruction to stop a power transmission operation to the DC-DC converter 330 of a battery module that transmits power to the power transmission bus 140, and (ii) an instruction to stop a power receiving operation to the DC-DC converter 330 of a battery module that receives power from the power transmission bus 140. The instruction management unit 742 may generate the above signal based on the voltage or SOC of each of the multiple power storage cells that make up the assembled battery 210 of each battery module. The instruction management unit 742 may generate the above signal based on the voltage or SOC of each of the assembled battery 210 of each battery module.

[0157] In this embodiment, the instruction management unit 742 manages information indicating the transmission destination of the signal 32 and information indicating the content of the signal 32, in association with each other. In one embodiment, the instruction management unit 742 manages information indicating the time when the signal 32 was transmitted, information indicating the transmission destination of the signal 32, and information indicating the content of the signal 32, in association with each other. In another embodiment, the instruction management unit 742 manages identification information of each battery module and information indicating the content of the latest signal 32 for each battery module, in association with each other.

[0158] In this embodiment, the operation management unit 744 manages the status of the equalization operation between the battery modules. For example, the operation management unit 744 manages the operation status of the DC-DC converters 330 arranged in the battery modules 114 and 116. The operation management unit 744 may obtain information indicating the operation status of each of the DC-DC converters 330 and manage the information.

[0159] For example, the operation management unit 744 acquires and manages information indicating at least one of the magnitude of the discharge voltage, the magnitude of the discharge current, the direction of the discharge current, the magnitude of the charge voltage, the magnitude of the charge current, and the direction of the charge current for each of the DC-DC converters 330. For example, the operation management unit 744 acquires and manages information indicating the operating status of the discharge control unit 642 and / or the charge control unit 644 for each of the DC-DC converters 330.

[0160] In this embodiment, the abnormality detection unit 746 detects an abnormality related to the equalization operation between the battery modules. For example, the abnormality detection unit 746 detects an abnormality in the DC-DC converters 330 arranged in the battery modules 114 and 116. More specifically, the abnormality detection unit 746 detects an abnormality related to the power transmission or power reception of the DC-DC converters 330.

[0161] The abnormality detection unit 746 may detect the above abnormality based on various information managed by the module management unit 720. When the above abnormality is detected, the abnormality detection unit 746 may output information indicating that the abnormality has been detected to the protection signal output unit 748.

[0162] In one embodiment, the abnormality detection unit 746 detects the abnormality when the direction of current in at least one of the low potential bus 142, the high potential bus 144, and the DC-DC converter 330 differs from a predetermined direction. Examples of the predetermined direction include (i) the direction of current when the equalization operation determined by the command management unit 742 is being performed normally, and (ii) a direction determined based on the voltage or SOC of the battery module 112.

[0163] For example, if the voltage or SOC of the battery module 112 is greater than a predetermined value, the direction from the battery module 112 to the power transmission bus 140 is determined as the predetermined direction. Similarly, if the voltage or SOC of the battery module 112 is less than a predetermined value, the direction from the power transmission bus 140 to the battery module 112 is determined as the predetermined direction.

[0164] In another embodiment, the abnormality detection unit 746 detects the abnormality when the magnitude of the current flowing from the high-potential bus 144 to the battery module 112 is greater than a predetermined value. Examples of the predetermined value include (i) the magnitude of the current when the equalization operation determined by the instruction management unit 742 is being performed normally, and (ii) the magnitude of the current determined based on the voltage or SOC of the battery module 112.

[0165] For example, the predetermined value is determined so that the greater the voltage or SOC of the battery module 112, the smaller the predetermined value. For example, the predetermined value is determined so that when the voltage or SOC of the battery module 112 is greater than a first value, the predetermined value is smaller than a second value.

[0166] The predetermined value may be smaller than the setting value for overcurrent protection of the protection unit 230. This allows the abnormality detection unit 746 to detect the abnormality before the protection unit 230 is activated. As a result, for example, blowing of a fuse disposed in the protection unit 230 is prevented.

[0167] In another embodiment, the abnormality detection unit 746 detects the abnormality when at least one of the magnitude and direction of the current flowing between the battery module 112 and the low-potential bus 142 meets a predetermined condition. Examples of the predetermined condition include a condition that the magnitude of the current flowing from the battery module 112 to the low-potential bus 142 is greater than a predetermined value, or a condition that the direction of the current flowing between the battery module 112 and the low-potential bus 142 is different from a predetermined first direction. The condition that the direction of the current flowing between the battery module 112 and the low-potential bus 142 is different from a predetermined first direction may be a condition that the direction of the current flowing between the battery module 112 and the high-potential bus 144 is different from a predetermined second direction.

[0168] Examples of the predetermined value include (i) the magnitude of the current when the equalization operation determined by the command management unit 742 is being performed normally, and (ii) the magnitude of the current determined based on the voltage or SOC of the battery module 112. For example, the predetermined value is determined so that the current increases as the voltage or SOC of the battery module 112 decreases compared to the voltages or SOC of the other battery modules 114 and / or 116. For example, the predetermined value is determined so that the smaller the difference between the voltage or SOC of the battery module 112 and the voltages or SOC of the other battery modules 114 and / or 116, the smaller the predetermined value.

[0169] The predetermined value may be smaller than the setting value for overcurrent protection of the protection unit 230. This allows the abnormality detection unit 746 to detect the abnormality before the protection unit 230 is activated. As a result, for example, blowing of a fuse disposed in the protection unit 230 is prevented.

[0170] Examples of the predetermined first direction include (i) the direction of current when the equalization operation determined by the command management unit 742 is being performed normally, and (ii) the direction of current determined based on the voltage or SOC of the battery module 112. This allows the battery pack 210 of the battery module 112 to be quickly protected, for example, even when a current smaller than the set value for overcurrent protection in the protection unit 230 of the battery module 112 flows in a direction different from that during normal times.

[0171] In still another embodiment, the abnormality detection unit 746 detects the abnormality when the status of the equalization operation in the battery module 112, the battery module 114, or the battery module 116 differs from a predetermined status. For example, the abnormality detection unit 746 detects the abnormality when the operation of the DC-DC converter 330 in the battery module 112, the battery module 114, or the battery module 116 differs from a predetermined operation. Examples of the predetermined operation include (i) an operation instructed by the instruction management unit 742, and (ii) an operation to generate a current of a specific magnitude in a specific direction.

[0172] In one embodiment, the abnormality detection unit 746 determines whether the status of the equalization operation or the operation of the DC-DC converter 330 differs from a predetermined operation, based on the content of the instruction related to the equalization operation for each battery module managed by the instruction management unit 742 and the status of the equalization operation for each battery module managed by the operation management unit 744. Examples of the equalization operation or the operation of the DC-DC converter 330 include the operation of the discharge control unit 642 and the operation of the charge control unit 644.

[0173] For example, when the instruction management unit 742 determines to supply power from the battery module 114 to the battery module 112 via the power transmission bus 140, the abnormality detection unit 746 compares the content of the instruction indicated by the signal 32 sent by the instruction management unit 742 to the battery module 114 with the operating status of the discharge control unit 642 and / or the charge control unit 644 indicated by the signal 62 and / or the signal 64 received by the operation management unit 744 from the battery module 114. If there is a contradiction between the two, the abnormality detection unit 746 detects an abnormality.

[0174] In another embodiment, the abnormality detection unit 746 determines whether the status of the equalization operation or the operation of the DC-DC converter 330 differs from a predetermined operation based on the magnitude of the voltage of each battery module managed by the voltage management unit 722, the magnitude and direction of the current flowing through each battery module managed by the current management unit 724, the magnitude of the voltage of each battery module managed by the SOC management unit 726, or a combination thereof. The magnitude and direction of the current flowing through each battery module may be measured, for example, by an ammeter (not shown) that measures the current at terminal 242 or terminal 244 of each battery module.

[0175] For example, the abnormality detection unit 746 compares (i) the magnitude of the current, the direction of the current, and / or the transition of the voltage or SOC of each battery module when the DC-DC converter 330 operates according to instructions from the system control unit 130 with (ii) the actually observed magnitude of the current, the direction of the current, and / or the transition of the voltage or SOC of each battery module. If there is a contradiction between the two, the abnormality detection unit 746 detects an abnormality.

[0176] In the present embodiment, the protection signal output unit 748 outputs the signal 28 for controlling the operation of the switching element 254 of the battery module 112. The signal 28 may be a signal for controlling the opening and closing operation of the switching element 254. The protection signal output unit 748 outputs the signal 28 when the abnormality detection unit 746 detects an abnormality. The protection signal output unit 748 may output the signal 28 when, for example, it receives a signal from the abnormality detection unit 746 indicating that an abnormality has been detected.

[0177] The protection signal output unit 748 may control the opening and closing operation of the switching element 254 so that (i) the switching element 254 opens the circuit 260 when the abnormality detection unit 746 does not detect an abnormality, and (ii) the switching element 254 closes the circuit 260 when the abnormality detection unit 746 detects an abnormality. For example, when the abnormality detection unit 746 detects an abnormality, the protection signal output unit 748 sends a signal 28 to the switching element 254 to close the circuit 260. In one embodiment, the switching element 254 is configured to open the circuit 260 when the signal 28 is not received. In another embodiment, when the abnormality detection unit 746 does not detect an abnormality, the protection signal output unit 748 may send a signal 28 to the switching element 254 to open the circuit 260.

[0178] The module balance management unit 740 may be an example of a control device. The abnormality detection unit 746 may be an example of a detection unit. The protection signal output unit 748 may be an example of a switching control unit.

[0179] 8 schematically illustrates an example of a control operation by the system control unit 130. In this embodiment, for the purpose of simplifying the explanation, an example of control related to the equalization operation between the battery modules will be explained using an example in which power is supplied from the battery module 114 to the battery module 112 via the power transmission bus 140.

[0180] 8 shows an example of a voltage fluctuation 820 of the battery module 112 and an example of a voltage fluctuation 840 of the battery module 114. A voltage fluctuation 822 indicates a voltage fluctuation of the battery module 112 when the DC-DC converter 330 of the battery module 114 is operating normally. A voltage fluctuation 824 indicates a voltage fluctuation of the battery module 112 when an abnormality occurs in the DC-DC converter 330 of the battery module 114. Similarly, a voltage fluctuation 842 indicates a voltage fluctuation of the battery module 114 when the DC-DC converter 330 of the battery module 114 is operating normally. A voltage fluctuation 844 indicates a voltage fluctuation of the battery module 114 when an abnormality occurs in the DC-DC converter 330 of the battery module 114.

[0181] According to this embodiment, at time t1, the voltage of the battery module 112 is V L and the voltage of the battery module 114 is V H Furthermore, at time t2, the system control unit 130 determines that the voltages of the battery modules 112 and 114 are V AV A signal 28 for controlling the operation of the DC-DC converter 330 of the battery module 114 is transmitted to the battery module 114 so that V AV is V L and V H It may be the average value of

[0182] When the DC-DC converter 330 of the battery module 114 operates normally, the voltage of the battery module 112 changes according to the voltage fluctuation 822, and the voltage of the battery module 114 changes according to the voltage fluctuation 842. On the other hand, when the DC-DC converter 330 of the battery module 114 does not operate normally, the voltages of the battery module 112 and the battery module 114 may not change as intended by the system control unit 130.

[0183] For example, if the DC-DC converter 330 fails, the DC-DC converter 330 may not perform the operation instructed by the command management unit 742 or may perform an operation different from the instructed operation. As a result, the potential difference between the low potential bus 142 and the high potential bus 144 may become larger or smaller than the target value set by the command management unit 742.

[0184] If the difference between the potential difference between the low potential bus 142 and the high potential bus 144 and the target value increases, the current or power flowing from the power transmission bus 140 to the battery module 112 may be larger than expected, or the current or power flowing from the battery module 112 to the power transmission bus 140 may be larger than expected. For example, if the magnitude of the current is smaller than the setting value of the overcurrent protection circuit provided in the protection unit 230 of the battery module, overcharging or overdischarging of the battery module may occur even if the protection unit 230 of the battery module is provided.

[0185] According to this embodiment, when an abnormality occurs in the DC-DC converter 330, the voltage of the battery module 112, which should normally increase, decreases, as shown by the voltage fluctuations 842 and 844. Also, the voltage of the battery module 114, which should normally decrease, increases.

[0186] However, according to the present embodiment, at time t3, the abnormality detection unit 746 detects an abnormality in the equalization operation between the battery modules. Also, the protection signal output unit 748 outputs a signal 28 for controlling the operation of the switching element 254 of the battery module 112. This closes the switching element 254, and the circuit 260 is short-circuited.

[0187] When the circuit 260 is short-circuited, a large current flows through the abnormal operation protection element 252. As a result, the resistance of the abnormal operation protection element 252 increases or the current flowing through the abnormal operation protection element 252 is cut off, thereby limiting the current flowing from the power transmission bus 140 to the assembled battery 210 of the battery module 112. This stops the voltage drop of the battery module 112 or reduces the rate at which the voltage drops. According to this embodiment, at times after time t3, the voltage of the battery module 112 is V FL As a result, the battery module 112 is prevented from being over-discharged.

[0188] Furthermore, when the switching element 254 is closed, the terminal 242 and the terminal 244 are electrically connected via the switching element 254. This causes the potential difference between the low potential bus 142 and the high potential bus 144 to become zero or approximately zero. As a result, the voltage of the battery module 114 stops increasing or the rate at which the voltage increases slows. According to this embodiment, at times after time t3, the voltage of the battery module 114 becomes V FH This prevents the battery module 114 from being overcharged.

[0189] As described above, according to this embodiment, if an abnormality in the equalization operation between the battery modules is detected, the equalization operation between the battery modules is stopped or the equalization speed is reduced, thereby constructing a safer battery pack 100 even if the DC-DC converter 330 fails.

[0190] 9 schematically illustrates another example of the internal configuration of the battery module 112. FIG. 9 illustrates an example of the battery module 112 in which the protection unit 230 has an overvoltage / overcurrent protection function. In this embodiment, the protection unit 230 includes a current detection unit 932, a switching element 934, and a protection circuit 936.

[0191] In this embodiment, the current detection unit 932 is disposed between the terminal 204 and the positive terminal of the battery pack 210. The current detection unit 932 detects the magnitude of a current flowing between the terminal 204 and the positive terminal of the battery pack 210. The current detection unit 932 may detect that a current greater than a predetermined value flows between the terminal 204 and the positive terminal of the battery pack 210.

[0192] The current detection unit 932 may be disposed between the terminal 204 and the connection point between the positive terminal of the battery pack 210 and the abnormal operation protection element 252. The current detection unit 932 may detect the magnitude of a current flowing between the terminal 204 and the connection point between the positive terminal of the battery pack 210 and the abnormal operation protection element 252. The current detection unit 932 may detect that a current greater than a predetermined value has flowed between the terminal 204 and the connection point between the positive terminal of the battery pack 210 and the abnormal operation protection element 252.

[0193] The current detection unit 932 outputs information indicating the magnitude of the detected current to the protection circuit 936. The current detection unit 932 may also output information indicating that a current greater than a predetermined value has flowed to the protection circuit 936.

[0194] The arrangement of the current detection unit 932 is not limited to this embodiment. In other embodiments, the current detection unit 932 is arranged between the terminal 202 and the negative terminal of the battery pack 210.

[0195] A known current detection sensor can be used as the current detection unit 932. The specific configuration of the current detection sensor is not particularly limited.

[0196] In this embodiment, the switching element 934 is disposed between the terminal 204 and the positive terminal of the battery pack 210. The current detection unit 932 may be disposed between the terminal 204 and the connection point between the positive terminal of the battery pack 210 and the abnormal operation protection element 252. The switching element 934 performs an ON or OFF operation based on a control signal from the protection circuit 936. For example, when the protection circuit 936 does not output a control signal, the switching element 934 maintains an ON state. When the switching element 934 receives a control signal from the protection circuit 936, the switching element 934 performs an OFF operation.

[0197] The arrangement of the switching element 934 is not limited to this embodiment. In other embodiments, the switching element 934 is arranged between the terminal 202 and the negative terminal of the battery pack 210.

[0198] The type of switching element 934 is not particularly limited, but examples of the switching element 934 include a mechanical switch and a semiconductor switch. Examples of the semiconductor switch include a transistor, a thyristor, and a triac. Examples of the transistor include a bipolar transistor (BJT) and a field effect transistor (FET).

[0199] In this embodiment, the protection circuit 936 has at least one function of undervoltage protection (sometimes referred to as UVP), overvoltage protection (sometimes referred to as OVP), and overcurrent protection (sometimes referred to as OCP). The protection circuit 936 realizes the above functions by, for example, controlling the operation of the switching element 934.

[0200] For example, the protection circuit 936 acquires information indicating the voltages of the plurality of power storage cells constituting the assembled battery 210 (sometimes referred to as cell voltage information) from the module control unit 490 of the balance correction unit 220. The cell voltage information may include information indicating the inter-terminal voltage of the assembled battery 210.

[0201] The protection circuit 936 determines whether the voltage of each storage cell indicated by the voltage information is within a predetermined range. If the voltage of at least one of the storage cells is lower than the lower limit of the range, the protection circuit 936 determines that the battery pack 210 is in a low-voltage state and outputs a signal to the switching element 934 to turn off the switching element 934. On the other hand, if the voltage of at least one of the storage cells is higher than the upper limit of the range, the protection circuit 936 determines that the battery pack 210 is in an overvoltage state and outputs a signal to the switching element 934 to turn off the switching element 934.

[0202] For example, the protection circuit 936 acquires information indicating the magnitude of the current detected by the current detection unit 932 (sometimes referred to as detected current information) from the current detection unit 932. As described above, the detected current information may be information indicating that a current greater than a predetermined value has been detected.

[0203] The protection circuit 936 determines whether the magnitude of the current indicated by the detected current information is greater than a predetermined value. If the detected current information includes information indicating that a current greater than the predetermined value has been detected, the protection circuit 936 may determine that the magnitude of the current indicated by the detected current information is greater than the predetermined value. If the magnitude of the current indicated by the detected current information is greater than the predetermined value, the protection circuit 936 determines that the battery pack 210 is in an overcurrent state and outputs a signal to the switching element 934 to turn off the switching element 934.

[0204] In one embodiment, the set value for determining whether the battery pack 210 is in an overcurrent state (sometimes referred to as the set value for the overcurrent of the battery pack 210) is set to be greater than the set value for the current magnitude of the abnormal operation protection element 252. When the switching element 934 is turned off, power transmission and reception between the battery module 112 and the external device is stopped. On the other hand, even if the abnormal operation protection element 252 is activated and power transmission and reception between the battery pack 210 and the power transmission bus 140 is stopped, power transmission and reception between the battery module 112 and the external device can continue. Therefore, when the set value for the current magnitude of the abnormal operation protection element 252 is smaller than the set value for the overcurrent of the battery pack 210, deterioration of the power storage cells due to malfunction of the equalization operation between the battery modules can be suppressed without sacrificing user convenience. In another embodiment, the set value for determining whether the battery pack 210 is in an overcurrent state and the set value for the current magnitude of the abnormal operation protection element 252 may be the same.

[0205] The protection circuit 936 may be configured with an analog circuit, a digital circuit, or a combination of an analog circuit and a digital circuit. The protection circuit 936 may be realized in hardware, software, or a combination of hardware and software.

[0206] 10 schematically illustrates another example of the internal configuration of the battery module 112. Fig. 10 illustrates an example of the battery module 112 in which the abnormal operation protection element 252 and the switching element 254 also function as the protection unit 230. The battery module 112 described in relation to Fig. 10 may have a similar configuration to the battery module 112 described in relation to Fig. 2, except that it does not include the protection unit 230 and the switching element 254 operates based on the signals 26 and 28.

[0207] According to this embodiment, when an abnormality in the equalization operation between the battery modules is detected, the switching element 254 shorts the circuit 260 based on the signal 28. On the other hand, when an overvoltage or overcurrent is detected in the battery pack 210, the switching element 254 shorts the circuit 260 based on the signal 26.

[0208] Fig. 11 schematically illustrates another example of the internal configuration of the DC-DC converter 330. An example of the DC-DC converter 330 will be described with reference to Fig. 11 , taking as an example a case where the charging control unit 644 is driven using power supplied from the power transmission bus 140. The DC-DC converter 330 described with reference to Fig. 11 may have a similar configuration to the DC-DC converter 330 described with reference to Fig. 6, except that it includes a current control circuit 1130.

[0209] In this embodiment, the current control circuit 1130 controls the magnitude of the discharge current (sometimes referred to as the output current of the battery module) of the assembled battery 210. This controls the magnitude of the current output from the assembled battery 210 via the power transmission bus 140.

[0210] In this embodiment, the current control circuit 1130 includes an overcurrent protection circuit 1132. The overcurrent protection circuit 1132 controls the magnitude of the output current so that the magnitude of the output current does not exceed a predetermined value. For example, when the potential difference between terminal 242 and terminal 244 decreases, the current control circuit 1130 controls the discharge control unit 642 so that the magnitude of the output current decreases. The current control circuit 1130 may control the discharge control unit 642 by outputting a signal 82 for controlling the discharge control unit 642. The overcurrent protection circuit 1132 will be described in detail below.

[0211] The current control circuit 1130 may be an example of a current control unit. The DC-DC converter 330, which operates using power supplied from the power transmission bus 140, may be an example of a power transmitting / receiving unit, which operates using power supplied from the first power line and the second power line.

[0212] 12 schematically illustrates an example of the circuit configuration of the overcurrent protection circuit 1232. The overcurrent protection circuit 1232 may be an example of the above-described overcurrent protection circuit 1132. The overcurrent protection circuit 1232 may be an example of an overcurrent protection circuit known as a foldback type or a foldback control type.

[0213] In this embodiment, the overcurrent protection circuit 1232 includes, for example, resistors 1212, 1214, and 1216, and a comparator 1220. For the purpose of simplifying the description, the positive and negative power supply terminals of the comparator 1220 are not shown in FIG. 12. The positive power supply terminal of the comparator 1220 is electrically connected to, for example, terminal 244. The negative power supply terminal of the comparator 1220 is electrically connected to, for example, terminal 242.

[0214] One end of the resistor 1212 is electrically connected to the terminal 244 and the inverting input terminal of the comparator 1220. The other end of the resistor 1212 is electrically connected to one end of the transformer 610 and one end of the resistor 1214. The other end of the resistor 1214 is electrically connected to the non-inverting input terminal of the comparator 1220 and one end of the resistor 1216. The other end of the resistor 1216 is electrically connected to one end of the diode 634 and the terminal 242. The other end of the diode 634 is electrically connected to the other end of the transformer 610. The comparator 1220 outputs a signal 82. The signal 82 output by the comparator 1220 is transmitted to the discharge control unit 642. The signal 82 may be a signal for controlling the operation of the pulse width modulator 1242 arranged in the discharge control unit 642.

[0215] 13 is a schematic diagram illustrating an example of a voltage-current characteristic of the overcurrent protection circuit 1232. As shown in characteristic 1300, the overcurrent protection circuit 1232 OUT is the overcurrent setting value I LIMIT When the output current I OUT and output voltage V OUT According to this embodiment, the output current I of the overcurrent protection circuit 1232 decreases. OUTEven if the voltage drops to 0V, the output current I OUT The magnitude of the output current I of the overcurrent protection circuit 1232 is greater than 0 [A] and smaller than the rated current. OUT When the voltage becomes 0V, the output current I OUT The magnitude of may be 0[A].

[0216] 14 schematically illustrates an example of the circuit configuration of the overcurrent protection circuit 1432. The overcurrent protection circuit 1432 may be an example of the above-described overcurrent protection circuit 1132. The overcurrent protection circuit 1432 may be an example of an overcurrent protection circuit known as a foldback type, a foldback control type, or the like.

[0217] In this embodiment, the overcurrent protection circuit 1432 includes, for example, a resistor 1212, a resistor 1214, a resistor 1216, a resistor 1412, a Zener diode 1420, and a comparator 1220. For the purpose of simplifying the explanation, the positive and negative power supply terminals of the comparator 1220 are not shown in FIG. 14. The positive power supply terminal of the comparator 1220 is electrically connected to, for example, the terminal 244. The negative power supply terminal of the comparator 1220 is electrically connected to, for example, the terminal 242.

[0218] One end of resistor 1212 is electrically connected to terminal 244 and the inverting input terminal of comparator 1220. The other end of resistor 1212 is electrically connected to one end of transformer 610 and one end of resistor 1214. The other end of resistor 1214 is electrically connected to the non-inverting input terminal of comparator 1220 and one end of resistor 1216. The other end of resistor 1216 is electrically connected to one end of resistor 1412 and one end of Zener diode 1420. The other end of Zener diode 1420 is electrically connected to one end of transformer 610, the other end of resistor 1212, and one end of resistor 1214. The other end of resistor 1412 is electrically connected to one end of diode 634 and terminal 242. The other end of diode 634 is electrically connected to the other end of transformer 610. Comparator 1220 outputs signal 82. The signal 82 output by the comparator 1220 is sent to the discharge control section 642. The signal 82 may be a signal for controlling the operation of the pulse width modulator 1242 arranged in the discharge control section 642.

[0219] 15 is a schematic diagram illustrating an example of a voltage-current characteristic of the overcurrent protection circuit 1432. As shown in characteristic 1500, the overcurrent protection circuit 1232 reduces the output current I OUT is the overcurrent setting value I LIMIT When the output current I OUT While the current remains constant, the output voltage V OUT V set until the output voltage V OUT The overcurrent protection circuit 1232 has a characteristic that the output voltage V OUT V set When the output current I OUT The output voltage V OUT It also has the property of reducing

[0220] 16 schematically illustrates an example of the circuit configuration of an overcurrent protection circuit 1632. The overcurrent protection circuit 1632 may be an example of the above-described overcurrent protection circuit 1132. The overcurrent protection circuit 1632 may be an example of an overcurrent protection circuit known as a drooping type, a fixed current limiting type, or the like.

[0221] In this embodiment, the overcurrent protection circuit 1632 includes, for example, a resistor 1612, a power supply 1620, and a comparator 1640. For the purpose of simplifying the description, the positive and negative power supply terminals of the comparator 1640 are not shown in FIG. 16. The positive power supply terminal of the comparator 1640 is electrically connected to, for example, the terminal 244. The negative power supply terminal of the comparator 1640 is electrically connected to, for example, the terminal 242.

[0222] One end of the transformer 610 is electrically connected to the terminal 244. One end of the resistor 1612 is electrically connected to the terminal 242 and the non-inverting input terminal of the comparator 1640. The other end of the resistor 1612 is electrically connected to the negative terminal of the power supply 1620 and one end of the diode 634. The positive terminal of the power supply 1620 is electrically connected to the inverting input terminal of the comparator 1640. The other end of the diode 634 is electrically connected to the other end of the transformer 610. The comparator 1640 outputs a signal 82. The signal 82 output by the comparator 1640 is transmitted to the discharge control unit 642. The signal 82 may be a signal for controlling the operation of the pulse width modulator 1242 arranged in the discharge control unit 642.

[0223] 17 shows a schematic example of a voltage-current characteristic of the overcurrent protection circuit 1632. As shown in characteristic 1700, the overcurrent protection circuit 1632 OUT is the overcurrent setting value I LIMIT When the output current I OUT While the current remains constant, the output voltage V OUT has the characteristic of drooping linearly.

[0224] 18 schematically illustrates an example of the circuit configuration of an overcurrent protection circuit 1832. The overcurrent protection circuit 1832 may be an example of the above-described overcurrent protection circuit 1132. The overcurrent protection circuit 1832 may be an example of an overcurrent protection circuit known as a constant power control voltage drooping type.

[0225] In this embodiment, the overcurrent protection circuit 1832 includes, for example, resistors 1812, 1814, 1816, and 1818, a power supply 1820, and comparators 1842 and 1844. For the purpose of simplifying the description, the positive and negative power supply terminals of the comparators 1842 and 1844 are not shown in FIG. 18 . The positive power supply terminal is electrically connected to, for example, terminal 244. The negative power supply terminal is electrically connected to, for example, terminal 242.

[0226] One end of the resistor 1812 is electrically connected to the terminal 242 and the non-inverting input terminal of the comparator 1844. The other end of the resistor 1812 is electrically connected to the negative terminal of the power supply 1820, one end of the resistor 1814, and one end of the diode 634. The other end of the resistor 1814 is electrically connected to the inverting input terminal of the comparator 1842, one end of the resistor 1816, and one end of the resistor 1818. The other end of the resistor 1816 is electrically connected to one end of the transformer 610 and the terminal 244. The other end of the resistor 1818 is electrically connected to the output terminal of the comparator 1842 and the inverting input terminal of the comparator 1844. The positive terminal of the power supply 1820 is electrically connected to the non-inverting input terminal of the comparator 1842. The other end of the diode 634 is electrically connected to the other end of the transformer 610. The comparator 1844 outputs a signal 82. The signal 82 output by the comparator 1844 is sent to the discharge control unit 642. The signal 28 may be a signal for controlling the operation of the pulse width modulator 1242 arranged in the discharge control unit 642.

[0227] 19 is a schematic diagram illustrating an example of a voltage-current characteristic of the overcurrent protection circuit 1832. As shown in characteristic 1900, the overcurrent protection circuit 1832 OUT is the overcurrent setting value I LIMIT When this is reached, the output voltage V OUT As the output current I OUT As shown in the characteristic 1900, the output current I of the overcurrent protection circuit 1832 increases. OUT is the set value I MAX is controlled so as not to exceed

[0228] 20 schematically illustrates an example of the internal configuration of the current control circuit 2030. The current control circuit 2030 differs from the current control circuit 1130 in that it includes an overcurrent protection circuit 1132 and a low-voltage protection circuit 2034. With respect to features other than the above differences, the current control circuit 2030 may have the same configuration as the current control circuit 1130.

[0229] In this embodiment, the low-voltage protection circuit 2034 controls the output of the battery pack 210 so that output from the battery pack 210 is stopped when the output voltage of the DC-DC converter 330 is lower than a predetermined value. For example, the low-voltage protection circuit 2034 controls the discharge control unit 642 so that the magnitude of the output current is reduced when the potential difference between the terminal 242 and the terminal 244 is lower than a predetermined value. According to this embodiment, when the voltage output from the battery pack 210 to the power transmission bus 140 via the DC-DC converter 330 is lower than a predetermined value, output from the battery pack 210 is stopped. This further improves the safety of the battery pack 100.

[0230] 21 is a schematic diagram showing an example of the voltage-current characteristic of the current control circuit 2030. Using FIG. 21, the operation of the low voltage protection circuit 2034 will be described, taking as an example the case where the overcurrent protection circuit 1132 of the current control circuit 2030 is the overcurrent protection circuit 1232. As shown in the characteristic 2100, the current control circuit 2030 reduces the output current I OUT is the overcurrent setting value I LIMIT When this is reached, the output voltage V OUT V UVP Until then, the output current I OUT and output voltage V OUT The current control circuit 2030 has the characteristic of reducing the output voltage V OUT V UVP When the output current I OUT When becomes 0 [V], the output current I OUT so that the magnitude of the output current I OUT and output voltage V OUTThe overcurrent protection circuit 1232 differs from the overcurrent protection circuit 1232 in that it has a characteristic of decreasing the current.

[0231] 20 and 21 , an example of the function of the low-voltage protection circuit 2034 has been described using an example in which the current control circuit 2030 includes the overcurrent protection circuit 1232 and the low-voltage protection circuit 2034. However, the current control circuit 2030 is not limited to this embodiment. In other embodiments, the current control circuit 2030 may include any type of overcurrent protection circuit and the low-voltage protection circuit 2034. For example, the current control circuit 2030 includes the overcurrent protection circuit 1432, the overcurrent protection circuit 1632, or the overcurrent protection circuit 1832, and the low-voltage protection circuit 2034.

[0232] 22 schematically shows an example of the system configuration of an electric vehicle 2200. In this embodiment, the electric vehicle 2200 includes a battery pack 100 and a motor 2210. The electric vehicle 2200 moves using the power of the battery pack 100. The motor 2210 generates power using the power of the battery pack 100.

[0233] According to this embodiment, for example, the battery module 112, the battery module 114, and the battery module 116 are arranged in different positions on the electric vehicle 2200. When multiple battery modules are arranged in different positions on the electric vehicle 2200, the environment surrounding each battery module differs depending on the location of the battery module. Examples of the environment include temperature, humidity, temperature changes, and humidity changes. Therefore, variations in the deterioration state among the multiple battery modules may increase over time. As a result, the balance of voltage or SOC among the multiple battery modules may deviate from the initial setting value. For example, when the electric vehicle 2200 is a large vehicle such as a bus or truck, the distance between the multiple battery modules is greater, and the above tendency becomes particularly pronounced.

[0234] However, according to the battery pack 100 of this embodiment, even if the voltage or SOC balance among the battery modules is lost, power can be transmitted and received among the battery modules. This allows the performance of the battery pack 100 to be restored. Furthermore, the battery pack 100 can be used efficiently.

[0235] The electric vehicle 2200 may be an example of an electric device or a moving object, and the motor 2210 may be an example of a load.

[0236] [An example of another embodiment] In this embodiment, the details of the electric device that uses electric power have been described using the electric vehicle 2200 as an example. However, the electric device is not limited to the electric vehicle 2200. The type of the electric device is not particularly limited, and in other embodiments, the electric device may be a stationary power supply facility or a power storage facility, or may be a home appliance.

[0237] In this embodiment, the details of a mobile object that moves using electric power have been described using the electric vehicle 2200 as an example. However, the mobile object is not limited to the electric vehicle 2200. The type of mobile object is not particularly limited, and examples of the mobile object include a vehicle, a ship, and an aircraft. Examples of vehicles include an automobile, a motorcycle, a stand-up vehicle with an electric unit, and a train. Examples of automobiles include an electric vehicle, a fuel cell vehicle, a hybrid vehicle, a small commuter vehicle, and an electric cart. Examples of motorcycles include an electric motorcycle, an electric three-wheeled motorcycle, and an electric bicycle. Examples of ships include a boat, a hovercraft, a jet ski, a submarine, a submersible, and an underwater scooter. Examples of aircraft include an airplane, an airship or balloon, a helicopter, and a drone.

[0238] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. For example, the details described for a particular embodiment can be applied to other embodiments to the extent that they are not technically inconsistent. Furthermore, each component may have the same features as other components with the same name but different reference numerals. It is apparent from the claims that such modifications and improvements can also be included within the technical scope of the present invention.

[0239] It should be noted that the execution order of each process, such as operations, procedures, steps, and stages, in the devices, systems, programs, and methods shown in the claims, specifications, and drawings is not specifically stated as "before," "prior to," etc., and that the processes can be performed in any order unless the output of a previous process is used in a subsequent process. Even if the operational flow in the claims, specifications, and drawings is described using "first," "next," etc. for convenience, this does not mean that the processes must be performed in this order. [Explanation of symbols]

[0240] 22 signal, 24 signal, 26 signal, 28 signal, 32 signal, 52 drive signal, 54 drive signal, 56 signal, 58 signal, 62 signal, 64 signal, 82 signal, 100 battery pack, 102 terminal, 104 terminal, 112 battery module, 114 battery module, 116 battery module, 130 system control unit, 140 power transmission bus, 142 low-potential bus, 144 high-potential bus, 202 terminal, 204 terminal, 210 assembled battery, 220 balance correction unit, 230 protection unit, 242 terminal, 244 terminal, 252 abnormal operation protection element, 254 switching element, 260 circuit, 330 DC-DC converter, 412 storage cell, 414 storage cell, 416 storage cell, 418 storage cell, 432 Balance correction circuit, 434 Balance correction circuit, 436 Balance correction circuit, 443 Connection point, 445 Connection point, 447 Connection point, 490 Module control unit, 545 Connection point, 550 Inductor, 552 Switching element, 554 Switching element, 562 Diode, 564 Diode, 570 Equalization control unit, 580 Voltage monitoring unit, 582 Voltage detection unit, 584 Voltage detection unit, 586 Difference detection unit, 610 Transformer, 622 Switching element, 624 Switching element, 632 Diode, 634 Diode, 642 Discharge control unit, 644 Charging control unit, 652 Current detection unit, 654 Current detection unit, 662 Capacitor, 664 Capacitor, 720 Module management unit, 722 Voltage management unit, 724 Current management unit, 726 SOC management unit, 728 Cell balance management unit, 740 Module balance control unit, 742, instruction control unit, 744, operation control unit, 746, abnormality detection unit, 748, protection signal output unit, 820, voltage fluctuation, 822, voltage fluctuation, 824, voltage fluctuation, 840, voltage fluctuation, 842, voltage fluctuation, 844, voltage fluctuation, 932, current detection unit, 934, switching element, 936, protection circuit, 1130, current control circuit, 1132, overcurrent protection circuit, 1212, resistor, 1214, resistor, 1216, resistor, 1220, comparator, 1232, overcurrent protection circuit, 1242, pulse width modulator, 1300, characteristics, 1412, resistor, 1420, Zener diode, 1432, overcurrent protection circuit, 1500, characteristics, 1612, resistor, 1620, power supply, 1632Overcurrent protection circuit, 1640 Comparator, 1700 Characteristics, 1812 Resistor, 1814 Resistor, 1816 Resistor, 1818 Resistor, 1820 Power supply, 1832 Overcurrent protection circuit, 1842 Comparator, 1844 Comparator, 1900 Characteristics, 2030 Current control circuit, 2034 Low voltage protection circuit, 2100 Characteristics, 2200 Electric vehicle, 2210 Motor

Claims

1. a power transmission / reception unit that transmits and receives power between a first assembled battery having a plurality of first storage cells connected in series and a second assembled battery having a plurality of second storage cells connected in series; a first power line electrically connected to a positive electrode terminal of the first assembled battery and electrically connected to a positive electrode terminal of the second assembled battery via the power transmitting and receiving unit; a second power line electrically connected to a negative electrode terminal of the first assembled battery and electrically connected to a negative electrode terminal of the second assembled battery via the power transmitting and receiving unit; a limiting unit that is disposed between the positive electrode terminal of the first assembled battery and the first power line or between the negative electrode terminal of the first assembled battery and the second power line, and that limits transmission and reception of power between the first assembled battery and the second assembled battery via the power transmitting and receiving unit; Equipped with the first assembled battery and the second assembled battery are connected in series, the power transmitting and receiving unit transmits and receives power between the first assembled battery and the second assembled battery via the first power line and the second power line; the limiting unit limits transmission and reception of power between the first assembled battery and the second assembled battery via the power transmitting and receiving unit when an abnormality related to power transmission or power reception of the power transmitting and receiving unit is detected; When a direction of a current in at least one of the first power line, the second power line, and the power transmitting and receiving unit is different from a predetermined direction, the abnormality in the power transmitting and receiving unit is detected. Energy storage system.

2. The limiting portion is When the abnormality of the power transmitting and receiving unit is detected, (i) reducing the current flowing from the second assembled battery to the first assembled battery via the first power line to a level lower than that before the abnormality was detected, or (ii) cutting off the current; The power storage system according to claim 1 .

3. Further comprising a protection unit that protects the first assembled battery from an overcurrent, the abnormality of the power transmitting and receiving unit is further detected when a magnitude of a current flowing from the first power line to the first assembled battery is greater than a predetermined value, or when a magnitude of a current flowing from the first assembled battery to the second power line is greater than a predetermined value; the predetermined value is lower than a set value for the protection unit to detect an overcurrent of the first assembled battery; The power storage system according to claim 1 or 2.

4. a short circuit connecting the positive electrode terminal of the first assembled battery, the limiting portion, and the negative electrode terminal of the first assembled battery in series; a switching unit that opens and closes the short circuit; Furthermore, the limiting unit limits transmission and reception of power between the first assembled battery and the second assembled battery via the power transmitting and receiving unit when the short circuit is closed; The opening and closing section is If the abnormality of the power transmitting and receiving unit is not detected, the short circuit is opened. If the abnormality of the power transmitting and receiving unit is detected, the short circuit is closed. The power storage system according to any one of claims 1 to 3.

5. a detection unit that detects the abnormality in the power transmitting and receiving unit; a switching control unit that controls an opening and closing operation of the switching unit when the detection unit detects the abnormality in the power transmitting and receiving unit; Further provided with The power storage system according to claim 4 .

6. The limiting portion includes at least one of a fuse, an electronic fuse, a PTC thermistor, and a switching element. The power storage system according to any one of claims 1 to 5.

7. The power transmitting and receiving unit includes an insulating bidirectional DC-DC converter. The power storage system according to any one of claims 1 to 6.

8. the first assembled battery has a first equalizer that equalizes voltages of the plurality of first storage cells, or the second assembled battery has a second equalizer that equalizes voltages of the plurality of second storage cells, The power storage system according to any one of claims 1 to 7.

9. a current control unit that controls a magnitude of an output current that is a current output from the second assembled battery via the power transmitting and receiving unit, The current control unit an overcurrent protection circuit that controls the magnitude of the output current so that the magnitude of the output current does not exceed a predetermined value; having The power storage system according to any one of claims 1 to 8.

10. The current control unit a low-voltage protection circuit that stops output from the second assembled battery when an output voltage that is a voltage output from the second assembled battery via the power transmitting and receiving unit is lower than a predetermined value; further comprising The power storage system according to claim 9 .

11. the power transmitting and receiving unit operates using power supplied from the first power line and the second power line. The power storage system according to claim 9 or 10.

12. the first assembled battery; the second assembled battery; Further provided with The power storage system according to any one of claims 1 to 11.

13. The predetermined direction is a direction determined based on the voltage or SOC of the first assembled battery. The power storage system according to any one of claims 1 to 12.

14. The power storage system according to any one of claims 1 to 13; a load that uses the power of the power storage system; and An electrical device comprising:

15. The electrical device is a mobile object that moves using power from the power storage system.

15. The electrical device according to claim 14.

16. A control device for controlling a power storage system, The power storage system includes: a power transmission / reception unit that transmits and receives power between a first assembled battery having a plurality of first storage cells connected in series and a second assembled battery having a plurality of second storage cells connected in series; a first power line electrically connected to a positive electrode terminal of the first assembled battery and electrically connected to a positive electrode terminal of the second assembled battery via the power transmitting and receiving unit; a second power line electrically connected to a negative electrode terminal of the first assembled battery and electrically connected to a negative electrode terminal of the second assembled battery via the power transmitting and receiving unit; a limiting unit that is disposed between the positive electrode terminal of the first assembled battery and the first power line or between the negative electrode terminal of the first assembled battery and the second power line, and that limits transmission and reception of power between the first assembled battery and the second assembled battery via the power transmitting and receiving unit; a short circuit connecting the positive electrode terminal of the first assembled battery, the limiting portion, and the negative electrode terminal of the first assembled battery in series; a switching unit that opens and closes the short circuit; Equipped with the first assembled battery and the second assembled battery are connected in series, the power transmitting and receiving unit transmits and receives power between the first assembled battery and the second assembled battery via the first power line and the second power line; the limiting unit limits transmission and reception of power between the first assembled battery and the second assembled battery via the power transmitting and receiving unit when the short circuit is closed; The control device a detection unit that detects an abnormality related to power transmission or power reception of the power transmitting and receiving unit; an opening / closing control unit that controls the opening / closing operation of the opening / closing unit; Equipped with The opening / closing control unit is (i) when the detection unit does not detect the abnormality in the power transmitting and receiving unit, the switching unit opens the short circuit, and (ii) when the detection unit detects the abnormality in the power transmitting and receiving unit, the switching unit controls the opening and closing operation of the switching unit so that the switching unit closes the short circuit; the detection unit detects the abnormality in the power transmission and reception unit when a direction of a current in at least one of the first power line, the second power line, and the power transmission and reception unit differs from a predetermined direction. Control device.

17. The storage battery system further includes a protection unit that protects the first assembled battery from an overcurrent, The detection unit When the magnitude of the current flowing from the first power line to the first assembled battery is greater than a predetermined value, or when the magnitude of the current flowing from the first assembled battery to the second power line is greater than a predetermined value, The abnormality of the power transmitting and receiving unit is further detected, the predetermined value is lower than a set value for the protection unit to detect an overcurrent of the first assembled battery; The control device of claim 16.

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