Energy Storage System

Abstract

A first energy storage device is arranged between a wiring and a first energy storage unit, and has a first switching unit that switches the electrical connection relationship of the wiring and the first energy storage unit based on the voltage difference between the wiring and the first energy storage unit. A second energy storage device is arranged between the wiring and a second energy storage unit, and has a second switching unit that switches the electrical connection relationship between the wiring and the second energy storage unit based on the voltage difference between the wiring and the second storage unit. The first energy storage unit may include a first type of secondary battery. The second energy storage unit may include a second type of secondary battery. The charging end voltage of the first energy storage unit is the full charge voltage of the first energy storage unit or less, and is greater than the charging end voltage of the second energy storage unit.

Description

[Technical field]

[0001] The present invention relates to an electricity storage system. [Background technology]

[0002] In a power storage system including a plurality of power storage modules, the power storage modules may be connected in parallel (for example, see Patent Document 1). Patent Documents 2 to 4 disclose power storage systems in which power storage modules can be actively inserted and removed. [Prior art document] [Patent documents] [Patent Document 1] Japanese Patent Application Laid-Open No. 11-98708 [Patent Document 2] International Publication No. 2017 / 086349 [Patent Document 3] International Publication No. 2017 / 086349 [Patent Document 4] JP 2019-092257 A Problem to be Solved

[0003] When multiple storage modules of different types are connected in parallel, depending on the combination of the types of the multiple storage modules, at least one type of storage module may not be able to fully exhibit its performance.

[0004] In a first aspect of the present invention, a power storage system is provided. The power storage system includes, for example, a first power storage device having a first power storage unit. The power storage system includes, for example, a second power storage device having a second power storage unit. The power storage system includes, for example, a wiring for connecting the first power storage device and the second power storage device in parallel. In the power storage system, the first power storage device includes, for example, a first switching unit that is disposed between the wiring and the first power storage unit and switches the electrical connection relationship between the wiring and the first power storage unit based on a voltage difference between the wiring and the first power storage unit. In the power storage system, the second power storage device includes, for example, a second switching unit that is disposed between the wiring and the second power storage unit and switches the electrical connection relationship between the wiring and the second power storage unit based on a voltage difference between the wiring and the second power storage unit. In the power storage system, the first power storage unit includes, for example, a first type of secondary battery. The second power storage unit includes, for example, a second type of secondary battery. The battery system of the first type of secondary battery is represented by a reaction formula that, in principle, does not cause irreversible changes in the battery system even if an overcharged state continues, for example. The battery system of the second type of secondary battery is represented by a reaction formula that, in principle, causes irreversible changes in the battery system if an overcharged state continues, for example. In the above power storage system, the charge end voltage of the first power storage unit is, for example, equal to or lower than the full charge voltage of the first power storage unit and is higher than the charge end voltage of the second power storage unit.

[0005] In a second aspect of the present invention, a power storage system is provided. The power storage system includes, for example, a first power storage device having a first power storage unit and a wiring for connecting in parallel a second power storage device having a second power storage unit. In the power storage system, the first power storage device includes, for example, a first switching unit disposed between the wiring and the first power storage unit and switches an electrical connection relationship between the wiring and the first power storage unit based on a voltage difference between the wiring and the first power storage unit. In the power storage system, the second power storage device includes, for example, a second switching unit disposed between the wiring and the second power storage unit and switches an electrical connection relationship between the wiring and the second power storage unit based on a voltage difference between the wiring and the second power storage unit. In the power storage system, the first power storage unit includes, for example, a first type of secondary battery. The second power storage unit includes, for example, a second type of secondary battery. The battery system of the first type of secondary battery is expressed by a reaction formula that, in principle, does not cause irreversible changes in the battery system even if an overcharged state continues. The battery system of the second type of secondary battery is represented by a reaction formula in which, in principle, an irreversible change occurs in the battery system if an overcharged state continues. In the above-mentioned power storage system, the charge end voltage of the first power storage unit is, for example, equal to or lower than the full charge voltage of the first power storage unit and is higher than the charge end voltage of the second power storage unit.

[0006] In the power storage system according to the first or second aspect, the full charge voltage of the first power storage unit may be lower than the charging voltage of a charging device that charges the first and second power storage devices connected in parallel. The power storage system according to the first or second aspect may include a charging voltage control unit that controls a set value of the charging voltage of the charging device. In the above power storage system, the charging device may charge the first and second power storage devices by a constant current method during at least a part of a charging period of the first and second power storage devices. In the above power storage system, the charging device may charge the first power storage device by a constant current method when the voltage of the first power storage unit is equal to or lower than a charging end voltage. In the above power storage system, the charging device may charge the first power storage device by a trickle charging method when the voltage of the first power storage unit is higher than a charging end voltage.

[0007] In the power storage system according to the first or second aspect, the first power storage device may include a limiting unit that is connected in parallel with the first switching unit between the wiring and the first power storage unit, has a resistance greater than that of the first switching unit, and passes a current in a direction from the wiring to the first power storage unit and suppresses current passing in a direction from the first power storage unit to the wiring. In the above power storage system, the limiting unit may include a current amount limiting unit that limits the amount of current flowing through the limiting unit. In the above power storage system, the limiting unit may include a current direction limiting unit that is connected in series with the current amount limiting unit and passes a current in a direction from the wiring to the first power storage unit and does not pass a current in a direction from the first power storage unit to the wiring.

[0008] In the power storage system according to the first or second aspect, the first power storage device may have a short-circuiting unit disposed between the wiring and the first power storage unit, connected in parallel with the first switching unit between the wiring and the first power storage unit, and for short-circuiting the first switching unit. In the above power storage system, the short-circuiting unit may include a short-circuit state switching unit that transitions to a state in which the short-circuiting unit shorts the first switching unit. In the above power storage system, when it is detected that the output current of the power storage system is larger than the charging current of the power storage system, or when it is predicted that the output current of the power storage system will be larger than the charging current of the power storage system, the short-circuit state switching unit may short-circuit the first switching unit.

[0009] In the above power storage system, the short circuit state switching unit may switch the state of the short circuit unit from a state in which the short circuit unit shorts the first switching unit to a state in which the short circuit unit does not short the first switching unit in at least one of the following cases: (i) when a predetermined period has elapsed since the short circuit state switching unit short-circuited the first switching unit, and (ii) when it is detected that the output current of the power storage system is smaller than the charging current of the power storage system, or when it is predicted that the output current of the power storage system will be smaller than the charging current of the power storage system. In the above power storage system, when the power storage system acquires information indicating that a load device that uses power supplied from the power storage system starts using power, the short circuit state switching unit may short-circuit the first switching unit. In the above power storage system, the short circuit state switching unit may short-circuit the first switching unit before the power storage system outputs a current.

[0010] The power storage system according to the first or second aspect may include a fluctuation suppression unit for suppressing fluctuations in an output voltage of the power storage system. In the above power storage system, the short-circuit state switching unit may short-circuit the first switching unit after the power storage system outputs a current. In the above power storage system, the fluctuation suppression unit may be arranged such that, when a load device that uses power supplied from the power storage system is electrically connected to the power storage system, the fluctuation suppression unit and the load device are connected in parallel.

[0011] The power storage system according to the first or second aspect may include a detection unit that detects that the power storage system has supplied power to the load device. In the power storage system, when the detection unit detects that the power storage system has supplied power to the load device, the short circuit state switching unit may short-circuit the first switching unit. In the power storage system, after the power storage system supplies power to the load device, the current consumption of the load device may increase continuously or stepwise. The power storage system may receive a request signal from the load device indicating the magnitude of the current to be supplied to the load device. The power storage system may output a current of the magnitude indicated by the request signal. In the power storage system, the load device may include a current consumption control unit that controls the amount of current consumption of the load device.

[0012] The power storage system according to the first or second aspect may include a plurality of first power storage devices connected in parallel. In the power storage system, at least two of the plurality of first power storage devices may have a short-circuit portion.

[0013] The above summary of the invention does not list all of the necessary features of the present invention. Also, subcombinations of these features may also be inventions. [Brief description of the drawings]

[0014] [Figure 1] 1 shows an example of a system configuration of a power supply system 10. [Diagram 2] 2 shows an example of a system configuration of a power storage module 110. [Diagram 3] 2 shows an example of a system configuration of a power storage module 130. [Figure 4] 2 shows an example of a system configuration of a module control unit 240. [Diagram 5] 2 shows an example of a circuit configuration of the power storage module 110. [Figure 6] 1 shows an example of a system configuration of a system control unit 140. [Figure 7] 4 shows an example of voltage fluctuations and current fluctuations in each power storage module. [Figure 8] 2 shows an example of fluctuations in the charging voltage applied to the power storage system 100. [Figure 9] 2 shows an example of output characteristics of the charging device 14. [Figure 10] 1 shows an example of a system configuration of a power storage module 1010. [Figure 11] 1 shows an example of a system configuration of a module control unit 1040. [Figure 12] 2 shows an example of a circuit configuration of a module control unit 1040. [Figure 13] 13 shows an example of a system configuration of a power storage module 1330. [Figure 14] 13 shows an example of a system configuration of a power storage module 1430. [Figure 15] 1 shows an example of a system configuration of a power supply system 10. [Figure 16] 16 shows an example of a system configuration of a power storage module 1630. [Figure 17] 16 illustrates an example of control by a module control unit 1640. [Figure 18] 1 shows a schematic diagram of an example of current fluctuations in a power supply system 10. [Figure 19] 19 shows an example of a system configuration of a power supply system 1910. [Figure 20] 16 illustrates an example of control by a module control unit 1640. [Figure 21] 19 illustrates a schematic diagram of an example of current fluctuations in a power supply system 1910. [Figure 22] 22 shows an example of a system configuration of a power supply system 2210. [Diagram 23] 16 illustrates an example of control by a module control unit 1640. [Figure 24] 22 shows a schematic diagram of an example of current fluctuations in a power supply system 2210. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the invention according to the claims. Not all of the combinations of features described in the embodiments are essential to the solution of the invention. In addition, the embodiments will be described with reference to the drawings, but in the description of the drawings, the same reference numbers may be used for the same or similar parts, and duplicate descriptions may be omitted.

[0016] 1 shows an example of a system configuration of a power supply system 10. In this embodiment, the power supply system 10 includes a charging device 14, a charging switching unit 16, and a power storage system 100. The power supply system 10 may further include a load device 20 and a load switching unit 26. In this embodiment, the power storage system 100 includes a connection terminal 102, a connection terminal 104, wiring 106 that electrically connects the connection terminal 102 and the connection terminal 104, a power storage module 110, a power storage module 130, and a system control unit 140.

[0017] For the purpose of simplifying the explanation, in this embodiment, the power supply system 10 and the power storage system 100 will be explained in detail by taking as an example a case where the power storage system 100 includes a single power storage module 110 and a single power storage module 130. However, the power supply system 10 and the power storage system 100 are not limited to this embodiment. In other embodiments, the power storage system 100 may include a plurality of power storage modules 110. Furthermore, the power storage system 100 may include a plurality of power storage modules 130.

[0018] In this embodiment, the power supply system 10 supplies power to the load device 20. In this embodiment, the power supply system 10 includes a power storage device (for example, the power storage system 100) and supplies power stored in the power storage device to the load device 20. However, the power supply system 10 is not limited to this embodiment. In other embodiments, the power supply system 10 may include a power generation device and supply power generated by the power generation device to the load device 20. The power supply system 10 may include a power storage device and a power generation device.

[0019] The power supply system 10 is used in, for example, a power storage device, an electric appliance, a transportation device, etc. Examples of the transportation device include an electric vehicle, a hybrid vehicle, an electric two-wheeler, a railroad car, an airplane, an elevator, and a crane. The power supply system 10 may be a stationary power storage device. The power supply system 10 may be a stationary power storage system manufactured or assembled by reusing a used power storage device removed from a transportation device.

[0020] In this embodiment, the charging device 14 supplies power to the power storage system 100. The charging device 14 receives power from, for example, a system power supply, and supplies the power to the power storage system 100. As a result, the power storage module 110 and the power storage module 130 are charged.

[0021] In one embodiment, during a period in which the power supply system 10 supplies power to the load device 20, or during at least a part of the period, the power received by the charging device 14 from the grid power supply is smaller than the power output by the power supply system 10. For example, the rated power of the output equipment of the power supply system 10 is smaller than the rated power of the power receiving equipment of the charging device 14.

[0022] When the power supply system 10 includes a plurality of output facilities, the rated power of a single output facility may be smaller than the rated power of the power receiving facility of the charging device 14. When the power supply system 10 can simultaneously supply power to a plurality of load devices 20, the rated value of power that can be supplied to a single load device 20 may be smaller than the rated power of the power receiving facility of the charging device 14. Furthermore, when the power supply system 10 includes a plurality of power receiving facilities, the total value of the rated power of one or more output facilities arranged in the power supply system 10 may be smaller than the rated power of a single power receiving facility, and the rated power of a single output facility arranged in the power supply system 10 may be smaller than the rated power of a single power receiving facility.

[0023] According to the above embodiment, most of the power consumed by the load device 20 can be covered by the power stored in the power storage system 100. Therefore, even if the power received by the charging device 14 from the grid power supply is smaller than the power output by the power supply system 10, the power supply system 10 can continue to supply power to the load device 20. This allows the power receiving equipment of the charging device 14 to be made smaller or simpler. In addition, the unit price of power received from the grid power supply can be reduced.

[0024] In another embodiment, the power that the charging device 14 receives from the power grid is greater than the power that the power supply system 10 outputs. This allows the power supply system 10 to continue supplying power to the load device 20 even when the remaining amount of stored power in the power storage system 100 is low.

[0025] In this embodiment, the charge switching unit 16 switches the electrical connection between the charging device 14 and the power storage system 100. For example, the charge switching unit 16 switches between a state in which the charging device 14 and the power storage system 100 are electrically connected and a state in which the charging device 14 and the power storage system 100 are electrically disconnected. In one embodiment, the charge switching unit 16 switches the electrical connection between the charging device 14 and the power storage system 100 based on a control signal from the charging device 14. In another embodiment, the charge switching unit 16 switches the electrical connection between the charging device 14 and the power storage system 100 based on a control signal from the system control unit 140.

[0026] The charge switching unit 16 may be realized by hardware, software, or a combination of hardware and software. The charge switching unit 16 may be realized by an analog circuit, a digital circuit, or a combination of an analog circuit and a digital circuit.

[0027] The charge switching unit 16 may have one or more elements. The charge switching unit 16 may have one or more switching elements. Each of the one or more switching elements may be disposed between the connection terminal 102 and the charging device 14, or between the connection terminal 104 and the charging device 14. Examples of the switching element include a relay, a thyristor, and a transistor. The thyristor may be a bidirectional thyristor (sometimes called a triac). The transistor may be a semiconductor transistor. The semiconductor transistor may be a bipolar transistor or a field effect transistor. The field effect transistor may be a MOSFET.

[0028] The charge switching unit 16 may have one or more DC-DC converters instead of or in addition to the switching elements. The DC-DC converters may be isolated DC-DC converters. The DC-DC converters may be unidirectional DC-DC converters or bidirectional DC-DC converters. The charge switching unit 16 may have a transformer instead of or in addition to the switching elements.

[0029] In this embodiment, the charge switching unit 16 constitutes a part of the charging device 14. However, the charge switching unit 16 is not limited to this embodiment. In other embodiments, the charge switching unit 16 may constitute a part of the power storage system 100.

[0030] In this embodiment, the load device 20 is electrically connected to the connection terminal 102 and the connection terminal 104, and receives power supplied by the power supply system 10. The load device 20 may be an electric device that consumes power, or may be a power storage device that stores power. When the load device 20 is a power storage device, the power supply system 10 functions as a charging device that charges the load device 20.

[0031] In this embodiment, the load switching unit 26 switches the electrical connection between the load device 20 and the power storage system 100. For example, the load switching unit 26 switches between a state in which the load device 20 and the power storage system 100 are electrically connected and a state in which the load device 20 and the power storage system 100 are electrically disconnected. In one embodiment, the load switching unit 26 switches the electrical connection between the load device 20 and the power storage system 100 based on a control signal from the load device 20. In another embodiment, the load switching unit 26 switches the electrical connection between the load device 20 and the power storage system 100 based on a control signal from the system control unit 140.

[0032] The load switching unit 26 may be realized by hardware, software, or a combination of hardware and software. The load switching unit 26 may be realized by an analog circuit, a digital circuit, or a combination of an analog circuit and a digital circuit.

[0033] The load switching unit 26 may have one or more elements. The load switching unit 26 may have one or more switching elements. Each of the one or more switching elements may be disposed between the connection terminal 102 and the load device 20, or between the connection terminal 104 and the load device 20. Examples of the switching element include a relay, a thyristor, and a transistor. The thyristor may be a bidirectional thyristor (sometimes called a triac). The transistor may be a semiconductor transistor. The semiconductor transistor may be a bipolar transistor or a field effect transistor. The field effect transistor may be a MOSFET.

[0034] The load switching unit 26 may include one or more DC-DC converters instead of or in addition to the switching elements. The DC-DC converters may be isolated DC-DC converters. The DC-DC converters may be unidirectional DC-DC converters or bidirectional DC-DC converters. The load switching unit 26 may include a transformer instead of or in addition to the switching elements.

[0035] In this embodiment, the load switching unit 26 constitutes a part of the load device 20. However, the load switching unit 26 is not limited to this embodiment. In other embodiments, the load switching unit 26 may constitute a part of the power supply system 10.

[0036] In this embodiment, the power storage system 100 accumulates electric power. In addition, the power storage system 100 supplies electric power to an external device in response to a request from the device. More specifically, the power storage system 100 is electrically connected to a charging device 14 and accumulates electric energy (sometimes referred to as charging the power storage system). In addition, the power storage system 100 is electrically connected to a load device 20 and supplies electric power to the load device 20 (sometimes referred to as discharging the power storage system 100).

[0037] In this embodiment, the power storage system 100 is electrically connected to the charging device 14 via the connection terminal 102 and the connection terminal 104. The power storage system 100 is also electrically connected to the load device 20 via the connection terminal 102 and the connection terminal 104. The connection terminal 102 and the connection terminal 104 may function as an interface between the power supply system 10 and a device external to the power supply system 10.

[0038] In this embodiment, each of the power storage module 110 and the power storage module 130 includes a power storage unit (not shown) that stores power. Furthermore, in this embodiment, the power storage module 110 and the power storage module 130 are connected in parallel using a wiring 106. That is, a positive terminal of the power storage module 110 and a positive terminal of the power storage module 130 are electrically connected by a part of the wiring 106, and a negative terminal of the power storage module 110 and a negative terminal of the power storage module 130 are electrically connected by another part of the wiring 106.

[0039] Each of the power storage module 110 and the power storage module 130 may be detachably held in a housing (not shown) of the power storage system 100. This allows each of the power storage module 110 and the power storage module 130 to be individually replaced.

[0040] In this embodiment, each of the power storage modules 110 and 130 can switch the connection relationship between the power storage unit of each power storage module and the wiring 106 based on a control signal from the system control unit 140 or a user operation. For example, each of the power storage modules 110 and 130 can electrically connect the power storage unit of each power storage module to the wiring 106 or electrically disconnect the power storage unit of each power storage module from the wiring 106 based on a control signal from the system control unit 140 or a user operation.

[0041] As a result, even if the voltage of a power storage module to be newly mounted in the power storage system 100 differs from the voltage of a power storage module already mounted in the power storage system 100, each of the multiple power storage modules included in the power storage system 100 can be individually replaced without worrying about damage or deterioration of the power storage modules. The reason for this is, for example, as follows.

[0042] Due to recent improvements in the performance of lithium-ion batteries, the impedance of lithium-ion batteries has been reduced to approximately 10 mΩ. For example, even if the voltage difference between two storage modules is only 0.4 V, when the two storage modules are connected in parallel, a large current of 40 A flows from the storage module with the higher voltage to the storage module with the lower voltage. As a result, the storage modules deteriorate or are damaged. The voltage of the storage module may be the voltage between the positive and negative terminals of the storage module (sometimes referred to as the terminal-to-terminal voltage of the storage module).

[0043] In order to prevent deterioration or damage of the storage modules due to the replacement work of the storage modules, when replacing one of the multiple storage modules connected in parallel, it is possible to adjust the voltages of the newly installed storage module and the already installed storage module over a period of time until the voltage difference between the two modules becomes extremely small before performing the replacement work of the storage modules. By making the voltage difference between the newly installed storage module and the already installed storage module extremely small, it is possible to prevent a large current from flowing through each storage module when replacing the storage module. As a result, it is possible to suppress deterioration or damage of the storage module. However, as the impedance of the lithium-ion battery becomes smaller, the allowable voltage difference between the newly installed storage module and the already installed storage module also becomes smaller, and the time required for adjusting the voltage difference may become very long.

[0044] In contrast, according to the power storage system 100 of this embodiment, each of the power storage modules 110 and 130 can switch the connection relationship between the power storage unit of each power storage module and the wiring 106 based on a control signal from the system control unit 140 or an operation by a user. Then, for example, the power storage module 110 can be replaced by the following procedure.

[0045] First, the user removes the old power storage module 110 from the power storage system 100. Next, before mounting the new power storage module 110 in the power storage system 100, the user performs an operation to electrically disconnect the power storage unit of the new power storage module 110 from the wiring 106. For example, the user manually operates a switching element disposed between the positive terminal and the power storage unit of the power storage module 110 to electrically disconnect the positive terminal and the power storage unit of the power storage module 110.

[0046] Thereafter, the user mounts the power storage module 110 in a state in which the positive terminal and the power storage unit are electrically disconnected in the power storage system 100. At this time, since the positive terminal and the power storage unit are electrically disconnected, no current flows between the power storage module 110 and the power storage module 130 even if the voltage difference between the power storage module 110 and the power storage module 130 is relatively large. Thereafter, when the voltage difference between the power storage module 110 and the power storage module 130 reaches an appropriate value, the system control unit 140 executes an operation for electrically connecting the power storage module 110 and the wiring 106. The system control unit 140 will be described in detail later.

[0047] As described above, according to the energy storage system 100 of this embodiment, when replacing or installing an energy storage module, it is not necessary to strictly adjust the voltage of the energy storage module newly installed in the energy storage system 100 and the voltage of the energy storage module already installed in the energy storage system 100. Therefore, the energy storage module can be easily and quickly replaced or installed.

[0048] [Differences between the power storage module 110 and the power storage module 130] In this embodiment, the specifications of the power storage unit of the power storage module 110 are different from those of the power storage unit of the power storage module 130. In one embodiment, the type of secondary battery constituting the power storage unit of the power storage module 110 is different from that of the power storage unit of the power storage module 130. In another embodiment, the battery system of the power storage module 110 is different from that of the power storage module 130. In yet another embodiment, the terminal voltage of the power storage module 110 is different from that of the power storage module 130. Details of the power storage module 110 and the power storage module 130 will be described later.

[0049] [Overview of system control unit 140] In this embodiment, the system control unit 140 controls each unit of the power storage system 100. For example, the system control unit 140 (i) determines the state of each unit of the power storage system 100, (ii) monitors the state of each unit of the power storage system 100, and (iii) controls the operation of each unit of the power storage system 100.

[0050] [Determining the system state] In one embodiment, the system control unit 140 determines the state of the power storage system 100. Examples of the state of the power storage system 100 include a charging state, a discharging state, a standby state, and a stopped state. For example, the system control unit 140 receives information related to a charging / discharging event. The system control unit 140 determines the state of the power storage system 100 based on the information related to the charging / discharging event.

[0051] The information on the charge / discharge event may be information indicating that the power storage system 100 has already been discharged or charged, or may be information indicating that the power storage system 100 will be discharged or charged. Examples of the information on the charge / discharge event include (i) a charge request or a discharge request from an external device such as the charging device 14 or the load device 20, (ii) information indicating that an external device is connected to the power storage system 100, (iii) information indicating the type of the external device, (iv) information indicating the operation of the external device, (v) information indicating the state of the external device, (vi) information indicating a user's instruction or operation for the external device, (vii) information indicating a user's instruction or operation for the power supply system 10 or the power storage system 100, and (viii) a combination thereof.

[0052] For example, the system control unit 140 determines that the power storage system 100 is in a charging state when it detects connection of the charging device 14 or when it receives a signal indicating the type of the charging device 14. The system control unit 140 may determine that the power storage system 100 is in a charging state when it receives a signal indicating that charging is to start from the charging device 14. The system control unit 140 may determine that the power storage system 100 is in a charging state when it receives a signal indicating that a regenerative current is occurring or that a regenerative current may be occurring from the load device 20.

[0053] For example, the system control unit 140 determines that the power storage system 100 is in a discharging state when it detects a connection of the load device 20 or when it receives a signal indicating the type of the load device 20. The system control unit 140 may determine that the power storage system 100 is in a discharging state when it receives a signal indicating that electric power is to be used from the load device 20. Examples of signals indicating that electric power is to be used include a signal indicating that the load device 20 is to be powered on, a signal indicating that the load device 20 is powered on, a signal indicating that the load device 20 is to be shifted to an operation mode, and a signal indicating that the load device 20 has shifted to an operation mode.

[0054] [System Status Monitoring] In another embodiment, the system control unit 140 monitors the state of the power storage system 100. For example, the system control unit 140 monitors the state of at least one of the power storage module 110 and the power storage module 130. The system control unit 140 may monitor the state of each of the power storage module 110 and the power storage module 130. The system control unit 140 may collect information on battery characteristics of the power storage unit included in each of the power storage module 110 and the power storage module 130. The information on the battery characteristics of the power storage unit may be at least one selected from a voltage value of the power storage unit, a current value flowing through the power storage unit, a battery capacity of the power storage unit, a temperature of the power storage unit, a deterioration state of the power storage unit, and a State Of Charge (SOC) of the power storage unit.

[0055] The information on the battery characteristics of the power storage unit (sometimes referred to as the battery characteristics of the power storage module. The battery characteristics of the power storage unit may be the battery characteristics of a single cell among the plurality of cells constituting the power storage module, or may be the battery characteristics of a combination of the plurality of cells.) may include at least one of information on the specifications of the power storage unit and information on the deterioration state of the power storage unit. Examples of the information on the specifications of the power storage unit include information on the type or model of the power storage unit, the connection state of the power storage unit, the type of charging method that can charge the power storage unit, the type of charging method that cannot charge the power storage unit, the rated battery capacity (sometimes referred to as the rated capacity), the rated voltage, the rated current, the energy density, the maximum charge / discharge current, the charging characteristics, the charging temperature characteristics, the discharging characteristics, the discharging temperature characteristics, the self-discharge characteristics, the charge / discharge cycle characteristics, the equivalent series resistance in the initial state, the battery capacity in the initial state, the SOC [%] in the initial state, the storage voltage [V], and the like. Examples of the charging method include the CCCV method, the CC method, and the trickle charging method.

[0056] Examples of the connection state of the power storage unit include the type of unit cells constituting the power storage unit, the number of the unit cells, and the connection format of the unit cells. Examples of the connection format of the unit cells include the number of unit cells connected in series and the number of unit cells connected in parallel. The energy density is expressed as the volumetric energy density [Wh / m 3 ] or gravimetric energy density [Wh / kg].

[0057] Examples of the information on the deterioration state of the power storage unit include information on the power storage unit at any time, such as (i) battery capacity in a fully charged state, (ii) SOC under a predetermined temperature condition, (iii) SOH (State Of Health), (iv) equivalent series resistance (DCR, sometimes referred to as internal resistance), and (v) usage time accumulated from an initial state or a predetermined timing, number of charges, charge amount, discharge amount, number of charge / discharge cycles, temperature stress factor, and at least one of overcurrent stress factor. The information on the battery characteristics of the power storage unit may be stored in association with information on the deterioration state of the power storage unit and information on the time when the information was acquired. The information on the battery characteristics of the power storage unit may store information on the deterioration state of the power storage unit at a plurality of times.

[0058] SOH [%] is expressed, for example, as the fully charged capacity at the time of degradation (e.g., the current fully charged capacity) [Ah]÷initial fully charged capacity [Ah]×100. There are no particular limitations on the method of calculating or estimating the SOH, but, for example, the SOH of the power storage unit is calculated or estimated based on at least one of the DC resistance value and the open circuit voltage value of the power storage unit. The SOH may be a value converted into a value under predetermined temperature conditions using an arbitrary conversion formula or the like.

[0059] The method for determining the deterioration state of the power storage unit is not particularly limited, and any currently known or future developed method can be used. In general, as the deterioration of the power storage unit progresses, the available battery capacity decreases and the equivalent series resistance increases. Therefore, for example, the deterioration state of the battery can be determined by comparing the current battery capacity, SOC, or equivalent series resistance with the initial battery capacity, SOC, or equivalent series resistance.

[0060] The SOC [%] is expressed, for example, as remaining capacity [Ah]÷full charge capacity [Ah]×100. There is no particular limitation on the method of calculating or estimating the SOC, but the SOC is calculated or estimated based on at least one of (i) the measurement result of the voltage of the power storage unit, (ii) IV characteristic data of the voltage of the power storage unit, and (iii) an integrated value of the current value of the power storage unit, for example. The SOC may be a value converted into a value under a predetermined temperature condition using an arbitrary conversion formula or the like.

[0061] The information on the battery characteristics of the power storage unit may be information on at least one of a charge time and a discharge time of the power storage unit. The charge time and the discharge time of the power storage unit may be a charge time and a discharge time of a power storage module including the power storage unit, respectively. In general, as the deterioration of the power storage unit progresses, the available battery capacity decreases and at least one of the charge time and the discharge time becomes shorter.

[0062] The information on the charging time of the power storage unit may include information indicating a ratio of the charging time of the power storage unit to the charging time of the power storage system 100. The information on the charging time of the power storage unit may include information indicating the charging time of the power storage system 100 and information indicating the charging time of the power storage unit. The charging time may be (i) the time during which a current or a voltage is applied to the power storage system 100 or the power storage unit in one charging operation, or (ii) the total time during which a current or a voltage is applied to the power storage system 100 or the power storage unit in one or more charging operations in a predetermined period.

[0063] The information on the charging time of the power storage unit may include information indicating a ratio of the number of times the power storage unit has been charged in a predetermined period to the number of times the power storage system 100 has been charged in the predetermined period. The information on the charging time of the power storage unit may include information indicating the number of times the power storage system 100 has been charged in a predetermined period, and information indicating the number of times the power storage unit has been charged in the period.

[0064] The information on the discharge time of the power storage unit may include information indicating a ratio of the discharge time of the power storage unit to the discharge time of the power storage system 100. The information on the discharge time of the power storage unit may include the discharge time of the power storage system 100 and the discharge time of the power storage unit. The above-mentioned discharge time may be (i) the time during which the power storage system 100 or the power storage unit supplies a current or a voltage in one discharge operation, or (ii) the total time during which the power storage system 100 or the power storage unit supplies a current or a voltage in one or more discharge operations in a predetermined period.

[0065] The information on the discharge time of the power storage unit may include information indicating a ratio of the number of times the power storage unit discharges in a predetermined period to the number of times the power storage system 100 discharges in the predetermined period. The information on the discharge time of the power storage unit may include the number of times the power storage system 100 discharges in a predetermined period and the number of times the power storage unit discharges in the predetermined period.

[0066] The system control unit 140 may transmit at least one of information on the battery characteristics of the power storage unit included in the power storage module 110 and information on the battery characteristics of the power storage unit included in the power storage module 130 to an external device. This allows the external device to use the information on the battery characteristics of the power storage unit. Examples of the external device include the charging device 14 and the load device 20. The external device may be an output device that outputs information to a user. Examples of the output device include a display device such as a display, or an audio output device such as a microphone.

[0067] The system control unit 140 may determine the performance of the power storage module based on information on the battery characteristics of the power storage module. When the battery characteristics of the power storage module do not satisfy a predetermined determination condition, the system control unit 140 may output information indicating that the performance of the power storage module is insufficient. The system control unit 140 may determine the determination condition based on the application of the power storage system 100.

[0068] In the present embodiment, a case has been described in which the system control unit 140 collects at least one of information regarding the battery characteristics of the power storage unit included in the power storage module 110 and information regarding the battery characteristics of the power storage unit included in the power storage module 130, and transmits the collected information to an external device. However, the power storage system 100 is not limited to this embodiment. In other embodiments, each of the power storage module 110 and the power storage module 130 may collect information regarding the battery characteristics of the power storage unit included in each power storage module, and transmit the collected information to an external device.

[0069] [Controlling system operation] In another embodiment, the system control unit 140 controls the operation of each unit of the power storage system 100. For example, the system control unit 140 controls the operation of at least one of the power storage module 110 and the power storage module 130. The system control unit 140 may switch the connection relationship between the power storage unit of the power storage module 110 and the wiring 106. The system control unit 140 may switch the connection relationship between the power storage unit of the power storage module 130 and the wiring 106.

[0070] The system control unit 140 may control the operation of at least one of the charging device 14 and the charging switching unit 16. The system control unit 140 may control the start and stop of power supply from the charging device 14 to the power storage system 100. The system control unit 140 may adjust a set value of at least one of the charging voltage and the charging current. The system control unit 140 may control the increase or decrease rate of at least one of the charging voltage and the charging current.

[0071] The system control unit 140 may control the operation of at least one of the load device 20 and the load switching unit 26. The system control unit 140 may control the start and stop of power supply from the power storage system 100 to the load device 20. The system control unit 140 may adjust a set value of at least one of the output voltage and the output current. The system control unit 140 may control the increase or decrease rate of at least one of the output voltage and the output current.

[0072] The system control unit 140 may determine the order in which the power storage units of the power storage modules are electrically connected to the wiring 106 based on the voltage of the power storage units of the power storage modules. For example, when the power storage system 100 starts operating and the power storage system 100 starts from a charging state, the system control unit 140 electrically connects the power storage units of the power storage modules with a lower voltage to the wiring 106 first. On the other hand, when the power storage system 100 starts operating and the power storage system 100 starts from a discharging state, the system control unit 140 electrically connects the power storage units of the power storage modules with a higher voltage to the wiring 106 first. The system control unit 140 may determine the order in which the power storage units of the power storage modules are electrically connected to the wiring 106 based on the terminal-to-terminal voltage of each power storage module.

[0073] In one embodiment, the system control unit 140 may transmit a signal for connecting the power storage unit to the wiring 106 to each power storage module in the determined order. In another embodiment, the system control unit 140 may select the power storage module with the smallest voltage or SOC or the power storage module with the largest voltage or SOC, and transmit a signal for connecting the power storage unit to the wiring 106 only to the selected power storage module.

[0074] The system control unit 140 may be realized by hardware or software. It may also be realized by a combination of hardware and software. In one embodiment, the system control unit 140 may be realized by an analog circuit, a digital circuit, or a combination of an analog circuit and a digital circuit. In another embodiment, the system control unit 140 may be realized by executing a program for controlling each unit of the system control unit 140 in a general information processing device including a data processing device having a CPU, a ROM, a RAM, a communication interface, etc.

[0075] A program that is installed in a computer and causes the computer to function as a part of the system control unit 140 according to this embodiment may include modules that define the operation of each part of the system control unit 140. These programs or modules act on a CPU or the like to cause the computer to function as each part of the system control unit 140.

[0076] The information processing described in these programs, when loaded into a computer, functions as specific means in which the software and the various hardware resources described above work together. These specific means realize the calculation or processing of information according to the intended use of the computer in this embodiment, thereby making it possible to construct a specific device according to the intended use. The programs may be stored in a computer-readable medium, or in a storage device connected to a network.

[0077] Note that "electrically connected" is not limited to a case where a specific element and other elements are directly connected. A third element may be interposed between the specific element and other elements. Also, it is not limited to a case where a specific element and other elements are physically connected. For example, the input winding and the output winding of a transformer are not physically connected, but are electrically connected. Furthermore, it includes not only a case where a specific element and other elements are actually electrically connected, but also a case where a specific element and other elements are electrically connected when a storage cell and a balance correction unit are electrically connected. Also, "connected in series" indicates that a specific element and other elements are electrically connected in series, and "connected in parallel" indicates that a specific element and other elements are electrically connected in parallel.

[0078] [Parallel connection of power storage module 110 and power storage module 130] As described above, the power storage module 110 and the power storage module 130 having different specifications are connected in parallel in the power storage system 100. Therefore, in this embodiment, the power supply system 10 or the power storage system 100 is constructed taking into consideration the difference in specifications between the power storage module 110 and the power storage module 130.

[0079] In recent years, there is an urgent need to establish a method for reusing storage batteries used in transportation equipment such as electric vehicles and hybrid vehicles. However, for example, storage batteries for electric vehicles and storage batteries for hybrid vehicles differ greatly in rated specification values ​​and deterioration states. For example, generally, the terminal voltage of a storage battery for an electric vehicle is higher than the terminal voltage of a storage battery for a hybrid vehicle. Also, the capacity of a storage battery for an electric vehicle is higher than the capacity of a storage battery for a hybrid vehicle.

[0080] Therefore, for example, when the power storage module 110 is manufactured using a secondary reused storage battery for an electric vehicle (sometimes referred to as a second-hand product or a recycled product), the power storage module 130 is manufactured using a secondary reused storage battery for a hybrid vehicle, and the two are connected in parallel to manufacture the power storage system 100, the terminal voltage of the power storage module 110 differs from the terminal voltage of the power storage module 130. Also, if the storage battery for the electric vehicle is a lithium-ion battery or the like, the power storage module 110 does not support trickle charging. On the other hand, if the storage battery for the hybrid vehicle is a nickel-metal hydride battery or the like, the power storage module 130 supports trickle charging.

[0081] Here, depending on the relationship between the number and terminal voltage of the storage batteries included in the power storage module 110 and the number and terminal voltage of the storage batteries included in the power storage module 130, the terminal voltage of the power storage module 130 becomes higher than the terminal voltage of the power storage module 110. In this case, the set value of the charging end voltage of the power storage module 110 is adjusted to a value equal to or lower than the charging end voltage of the power storage module 130 or a value smaller than the charging end voltage.

[0082] In this case, when the power storage module 110 supports the trickle charging method and the power storage module 130 does not support the trickle charging method, trickle charging of the power storage module 110 may be continued after charging of the power storage module 110 is completed until the power storage module 110 reaches a full charge voltage. However, depending on the relationship between the type of storage battery included in the power storage module 110 and the type of storage battery included in the power storage module 130, there may be cases where the power storage module 110 does not support the trickle charging method and the power storage module 130 supports the trickle charging method. In this case, the operation and settings of the charging device 14 are determined taking into consideration the trickle charging of the power storage module 130.

[0083] When the power storage module 130 supports trickle charging, the charging end voltage of the power storage module 130 is equal to or lower than the fully charged voltage of the power storage module 130. As described above, in this embodiment, the charging end voltage of the power storage module 130 is higher than the charging end voltage of the power storage module 110 that does not support trickle charging. Therefore, according to this embodiment, the charging voltage of the charging device 14 is set to a value higher than the charging end voltage of the power storage module 130.

[0084] As a result, after charging of the power storage module 130 is completed, trickle charging of the power storage module 130 can be continued until the power storage module 130 reaches a full charge voltage. The charging end voltage of the power storage module 130 is determined, for example, by the number of storage batteries included in the power storage module 130 and the terminal voltage. The charging end voltage of the power storage module 110 is determined, for example, by the number of storage batteries included in the power storage module 110 and the terminal voltage.

[0085] The charging end voltage of the energy storage module may be a voltage at which the energy storage module is permitted to be charged in a constant current region. The set value of the charging end voltage is specified, for example, by a manufacturer or seller of the energy storage module, or a designer of the energy storage system 100. The full charge voltage of the energy storage module may be a voltage in a state where the charging rate of the energy storage module increases due to trickle charging, and then the rate of increase in the charging rate becomes lower than a predetermined value. The value of the full charge voltage of the energy storage module is greater than the value of the charging end voltage of the energy storage module.

[0086] For example, after starting charging of the storage module, the charging device 14 charges the storage module by a relatively high-speed charging method such as a constant current charging method, a constant voltage charging method, or a constant current / constant voltage charging method until the voltage or charging rate (sometimes referred to as SOC) of the storage module reaches a first value. Thereafter, the charging device 14 reduces the charging current and starts charging by a trickle charging method. While the storage module is being charged by the trickle charging method, the voltage of the storage module slowly increases until the voltage of the storage module reaches a second value. When the voltage of the storage module reaches the second value, the voltage of the storage module hardly increases. For example, in the case where the storage module includes a plurality of storage cells and an equalization circuit that equalizes the voltages of the plurality of storage cells, the voltages of the plurality of storage cells included in the storage module are equalized while the storage module is being charged by the trickle charging method. As a result, the voltage of the storage module hardly increases. In this case, the first value may be an example of a charging end voltage. The second value may be an example of a fully charged voltage.

[0087] As described above, by constructing the power storage system 100 by combining different types of secondary batteries in parallel, it is possible to construct a power supply system that is superior in at least one of lifespan, reliability, charging performance, discharging performance, energy efficiency, temperature characteristics, and economy, compared to the power storage system 100 consisting of a single type of secondary battery. For example, a lead battery operates in a relatively wide temperature range, but has a relatively low energy efficiency in charging and discharging. On the other hand, a lithium ion battery has a high energy efficiency in charging and discharging, but has a problem in operating in low and high temperature regions. Therefore, by combining a power storage module having a power storage unit consisting of a lead battery and a power storage module having a power storage unit consisting of a lithium ion battery in parallel, a power supply system that operates in a wide temperature range and has high energy efficiency can be constructed.

[0088] Furthermore, nickel-metal hydride batteries (for example, NiMH batteries) are characterized by their resistance to low temperature operation and the large amount of power that can be drawn instantaneously, compared to lithium-ion batteries. Therefore, by combining in parallel a power storage module having a power storage unit made of nickel-metal hydride batteries with a power storage module having a power storage unit made of lithium-ion batteries, it is possible to construct a power supply system that operates over a wide temperature range, can draw large amounts of power instantaneously, and has a large battery capacity.

[0089] The power supply system 10 may be an example of a power storage system. The power storage system 100 may be an example of a power storage system. The power storage module 110 may be an example of a second power storage device. The power storage unit of the power storage module 110 may be an example of a second power storage unit. The power storage module 130 may be an example of a first power storage device. The power storage unit of the power storage module 130 may be an example of a second power storage unit. The system control unit 140 may be an example of a charging voltage control unit. The system control unit 140 may be an example of a current consumption control unit.

[0090] In the present embodiment, the power storage system 100 is described as including two power storage modules connected in parallel. However, the power storage system 100 is not limited to this embodiment. In other embodiments, the power storage system 100 may include three or more power storage modules connected in parallel.

[0091] In the present embodiment, a case has been described in which a user performs an operation for electrically connecting the power storage unit of a new power storage module 110 to the wiring 106 before mounting the power storage module 110 in the power storage system 100. However, the mounting method or replacement method of the power storage module 110 is not limited to this embodiment. In other embodiments, the user operates, for example, an input unit (not shown) of the power storage system 100 to input an instruction for starting the replacement work of the power storage module 110. Examples of the input unit include a keyboard, a pointing device, a touch panel, a microphone, a voice recognition system, and a gesture input system.

[0092] When the system control unit 140 receives an instruction to start the replacement work of the power storage module 110, the system control unit 140 may perform an operation to electrically disconnect the wiring 106 from the power storage unit of the power storage module (power storage module 130 in this embodiment) connected in parallel to the power storage module 110. At this time, the system control unit 140 may perform an operation to electrically disconnect the power storage unit of the power storage module 110 from the wiring 106. For example, the system control unit 140 transmits a signal to a switching element arranged between the positive terminal and the power storage unit of each power storage module to turn off the switching element.

[0093] When the system control unit 140 detects that the old power storage module 110 has been removed and a new power storage module 110 has been installed, the system control unit 140 acquires the voltage of the power storage unit of each power storage module. When the power storage unit of the new power storage module 110 is electrically connected to the wiring 106, the system control unit 140 operates the power storage system 100 using only the power storage module 110, for example, until the voltage difference between the power storage module 110 and the power storage module 130 reaches an appropriate value. Then, when the voltage difference between the power storage module 110 and the power storage module 130 reaches an appropriate value, the system control unit 140 executes an operation to electrically connect the power storage module 130 to the wiring 106.

[0094] On the other hand, when the power storage unit of the new power storage module 110 is not electrically connected to the wiring 106, the system control unit 140 determines the order in which the power storage unit of each power storage module is electrically connected to the wiring 106 based on the voltage of the power storage unit of each power storage module. Thereafter, the system control unit 140 electrically connects the power storage unit of each power storage module to the wiring 106 according to the determined order. Note that, when the power storage unit of the new power storage module 110 is electrically connected to the wiring 106, the system control unit 140 may first electrically disconnect the power storage unit of the new power storage module 110 from the wiring 106. Thereafter, the system control unit 140 may determine the order in which the power storage unit of each power storage module is electrically connected to the wiring 106 based on the voltage of the power storage unit of each power storage module, and electrically connect the power storage unit of each power storage module to the wiring 106 according to the determined order.

[0095] 2 illustrates an example of a system configuration of the power storage module 110. In this embodiment, the power storage module 110 includes a positive terminal 202 and a negative terminal 204. The power storage module 110 also includes a power storage unit 210 having a positive terminal 212 and a negative terminal 214, and a switching unit 230. In this embodiment, the power storage unit 210 includes a power storage cell 222 and a power storage cell 224. In this embodiment, the power storage module 110 further includes a module control unit 240, a protection unit 250, and a balance correction unit 260.

[0096] The impedance of the power storage unit 210 may be 1 Ω or less, or may be 100 mΩ or less. The impedance of the power storage unit 210 may be 10 mΩ or less, 1 mΩ or less, 0.8 mΩ or less, or 0.5 mΩ or less. The impedance of the power storage unit 210 may be 0.1 mΩ or more. The impedance of the power storage unit 210 may be 0.1 mΩ or more and 1 Ω or less, 0.1 mΩ or more and 100 mΩ or less, 0.1 mΩ or more and 10 mΩ or less, or 0.1 mΩ or more and 1 mΩ or less.

[0097] According to the power storage system 100 of this embodiment, for example, when replacing one of a plurality of power storage modules connected in parallel, it is not necessary to match the voltage of the power storage module newly added to the power storage system with the voltage of the remaining power storage modules with high accuracy. Therefore, even if the impedance of the power storage unit 210 is small, the power storage module 110 can be easily and quickly replaced.

[0098] In this embodiment, the power storage cell 222 and the power storage cell 224 are connected in series. The power storage cell 222 and the power storage cell 224 may be secondary batteries or capacitors. At least one of the power storage cell 222 and the power storage cell 224 may further include a plurality of power storage cells connected in series, in parallel, or in a matrix shape inside the power storage cell.

[0099] In this embodiment, each of the storage cell 222 and the storage cell 224 is formed of a type of secondary battery that does not support trickle charging. At least one of the storage cell 222 and the storage cell 224 may be a lithium ion battery.

[0100] Generally, if no irreversible changes occur in the battery system of a secondary battery in an environment where charging continues in a fully charged state (that is, if the chemical reactions of the battery system of the secondary battery in an overcharged state are expressed by a reaction formula that does not involve irreversible changes), the secondary battery can support trickle charging. Examples of secondary batteries that can support trickle charging include lead batteries, nickel-metal hydride batteries, and nickel-cadmium batteries. The chemical reactions of the battery systems of lead batteries, nickel-metal hydride batteries, and nickel-cadmium batteries during normal charging and discharging are expressed by the following formulas (1) to (3), respectively. PbO2+Pb+2H2SO4⇔ PbSO4+PbSO4+2H2O …(1) NiOOH+MH ⇔ Ni(OH)2+ M …(2) 2NiOOH+Cd+2H2O ⇔ 2Ni(OH)2+Cd(OH)2…(3) On the other hand, if irreversible changes occur in the battery system of a secondary battery in an environment where charging continues in a fully charged state (that is, if the chemical reaction of the battery system of a secondary battery in an overcharged state is expressed by a reaction formula involving irreversible changes), the secondary battery cannot support trickle charging. Examples of secondary batteries that cannot support trickle charging include lithium batteries and lithium ion batteries (including lithium ion polymer batteries and all-solid-state batteries). Among the above secondary batteries, the chemical reaction of the battery system of a lithium ion battery during normal charging and discharging is expressed by the following formula (4). Li (1-x) CoO2+Li x C6⇔LiCoO2+C6…(4) In the chemical reaction when a lithium-ion battery is overcharged, the crystal structure of the positive electrode active material, lithium cobalt oxide, collapses due to overcharging, generating oxygen. This generation of oxygen due to overcharging occurs when the lithium cobalt oxide (Li (1-x) This causes an imbalance between cobalt dioxide (CoO2) and cobalt oxide (CoO2), and the original crystal structure will not return, resulting in a decrease in the positive electrode capacity, and is therefore considered an irreversible change. Trickle charging can be defined as a charging method in which a secondary battery in a fully charged state or a state close to being fully charged is continuously or intermittently charged with a minute current. In this embodiment, trickle charging is embodied as a charging method in which, after the completion of charging a trickle-charging compatible storage module, the storage module is continuously charged with a current smaller than the charging current during normal charging, so as to bring the storage module closer to a fully charged state. Thus, in this embodiment, the minute current for trickle charging is a current that can increase the charge amount of the target storage module, but when the charge state at the completion of charging is closer to being fully charged, it can also be a current that can compensate for the decrease in the charge amount due to natural discharge of the target storage module.

[0101] In this embodiment, the positive electrode terminal 212 of the power storage unit 210 is electrically connected to the wiring 106 via the positive electrode terminal 202 of the power storage module 110 and the switching unit 230. Meanwhile, the negative electrode terminal 214 of the power storage unit 210 is electrically connected to the wiring 106 via the negative electrode terminal 204 of the power storage module 110. However, the power storage module 110 is not limited to this embodiment. In another embodiment, the negative electrode terminal 214 of the power storage unit 210 is electrically connected to the wiring 106 via the negative electrode terminal 204 of the power storage module 110 and the switching unit 230. Meanwhile, the positive electrode terminal 212 of the power storage unit 210 is electrically connected to the wiring 106 via the positive electrode terminal 202 of the power storage module 110.

[0102] In this embodiment, the switching unit 230 is disposed between the wiring 106 and the power storage unit 210. In this embodiment, the switching unit 230 switches the electrical connection relationship between the wiring 106 and the power storage unit 210 based on a voltage difference between the wiring 106 and the power storage unit 210. For example, the switching unit 230 switches the connection state between the wiring 106 and the power storage unit 210 based on a signal generated by the module control unit 240. This makes it possible to electrically connect the power storage unit 210 to the wiring 106 or electrically disconnect the power storage unit 210 from the wiring 106.

[0103] When the power storage module 110 is implemented in the power storage system 100, the power storage module 110 may be attached to the power storage system 100 in a state in which the power storage unit 210 and the wiring 106 are electrically disconnected by the switching unit 230. This makes it possible to prevent damage or deterioration of the power storage module 110.

[0104] The switching unit 230 may be realized by hardware, software, or a combination of hardware and software. The switching unit 230 may be realized by an analog circuit, a digital circuit, or a combination of an analog circuit and a digital circuit.

[0105] The switching unit 230 may have one or more elements. The switching unit 230 may have one or more switching elements. Each of the one or more switching elements may be disposed between the positive terminal 202 and the positive terminal 212, or between the negative terminal 204 and the negative terminal 214. Examples of the switching element include a relay, a thyristor, and a transistor. The thyristor may be a bidirectional thyristor (sometimes called a triac). The transistor may be a semiconductor transistor. The semiconductor transistor may be a bipolar transistor or a field effect transistor. The field effect transistor may be a MOSFET.

[0106] The switching unit 230 may include one or more DC-DC converters instead of or in addition to the switching elements. The DC-DC converters may be isolated DC-DC converters. The DC-DC converters may be unidirectional DC-DC converters or bidirectional DC-DC converters. The switching unit 230 may include a transformer instead of or in addition to the switching elements.

[0107] The module control unit 240 controls a current flowing between the power storage unit 210 of the power storage module 110 and the wiring 106. In this embodiment, the module control unit 240 controls the switching unit 230 so that the switching unit 230 electrically connects the power storage unit 210 and the wiring 106 when the terminal voltage of the switching unit 230 (in this embodiment, the voltage between the positive terminal 202 and the positive terminal 212) satisfies a predetermined condition. The switching unit 230 may electrically connect the power storage unit 210 and the wiring 106 by electrically connecting the power storage unit 210 and the positive terminal 202.

[0108] On the other hand, when the terminal voltage of the switching unit 230 does not satisfy the predetermined condition, the switching unit 230 controls the switching unit 230 so as to electrically disconnect the power storage unit 210 and the wiring 106 or the positive terminal 202. The switching unit 230 may electrically disconnect the power storage unit 210 and the wiring 106 by electrically disconnecting the power storage unit 210 and the positive terminal 202.

[0109] The predetermined condition may be a condition that the absolute value of the terminal voltage of the switching unit 230 is within a predetermined range. The predetermined range may be 3V or less, 1V or less, 0.1V or less, 10mV or less, or 1mV or less. The predetermined range may be 0.5mV or more, or 1mV or more. The predetermined range may be 0.5mV or more and 3V or less. The predetermined range may be 1mV or more and 3V or less, 1mV or more and 1V or less, 1mV or more and 0.1V or less, 1mV or more and 10mV or less, 10mV or more and 1V or less, 10mV or more and 0.1V or less, or 0.1V or more and 1V or less. The terminal voltage of the switching unit 230 may be the voltage between the positive terminal 202 and the positive terminal 212, or may be the voltage between the wiring 106 and the power storage unit 210.

[0110] The predetermined range may be set based on the impedance of the power storage unit 210. The predetermined range may be set based on the rated current or allowable current of the power storage unit 210. The predetermined range may be set based on the impedance of the power storage unit 210 and the rated current or allowable current of the power storage unit 210. The predetermined range may be set based on the rated current or allowable current of an element having the smallest rated current or allowable current among the elements constituting the power storage module 110. The predetermined range may be set based on the impedance of the power storage module 110 and the rated current or allowable current of an element having the smallest rated current or allowable current among the elements constituting the power storage module 110.

[0111] As a result, when replacing a power storage module, the wiring 106 and the power storage unit 210 of the newly mounted power storage module can be maintained in an electrically disconnected state until the voltage difference between the newly mounted power storage module and the already mounted power storage module falls within a predetermined range. Then, when the voltage difference between the newly mounted power storage module and the already mounted power storage module falls within a predetermined range due to charging or discharging of the already mounted power storage module, the power storage unit of the newly mounted power storage module is electrically connected to the wiring 106. In this way, according to this embodiment, the newly mounted power storage module can be automatically connected to other power storage modules.

[0112] In this embodiment, the module control unit 240 receives a signal indicating that the terminal voltage of the power storage module 110 is smaller than the terminal voltages of the other power storage modules from the system control unit 140. When the module control unit 240 receives the above signal when the power storage system 100 transitions to a charging state, the module control unit 240 controls the switching unit 230 so that the switching unit 230 electrically connects the power storage unit 210 and the wiring 106. This makes it possible to efficiently charge the multiple power storage modules 110 connected in parallel.

[0113] In this embodiment, the module control unit 240 receives a signal indicating that the terminal voltage of the power storage module 110 is greater than the terminal voltages of the other power storage modules from the system control unit 140. When the module control unit 240 receives the above signal when the power storage system 100 transitions to a discharging state, the module control unit 240 controls the switching unit 230 so that the switching unit 230 electrically connects the power storage unit 210 and the wiring 106. This allows the multiple power storage modules 110 connected in parallel to be efficiently discharged.

[0114] In this embodiment, the module control unit 240 receives a signal indicating that the terminal voltage of the power storage cell 222 or the power storage cell 224 is not within a predetermined range from the protection unit 250. Upon receiving the signal, the module control unit 240 controls the switching unit 230 so that the switching unit 230 electrically disconnects the power storage unit 210 and the wiring 106. This makes it possible to suppress deterioration or damage of the power storage unit 210 due to overcharging or overdischarging.

[0115] In this embodiment, the module control unit 240 accepts a user operation and receives an instruction from the user to turn on or off the switching unit 230. Upon receiving the user's instruction, the module control unit 240 controls the switching unit 230 in accordance with the instruction.

[0116] In this embodiment, the module control unit 240 may acquire information on the battery characteristics of the power storage unit 210. The module control unit 240 may output the information on the battery characteristics of the power storage unit 210 to an external device. This allows the external device to use the information on the battery characteristics of the power storage unit 210. Examples of the external device include the load device 20 and the charging device 14. The external device may be an output device that outputs information to a user.

[0117] The module control unit 240 may be realized by hardware or software. Also, it may be realized by a combination of hardware and software. In one embodiment, the module control unit 240 may be realized by an analog circuit, a digital circuit, or a combination of an analog circuit and a digital circuit. In another embodiment, the module control unit 240 may be realized by executing a program for controlling the module control unit 240 in a general information processing device including a data processing device having a CPU, a ROM, a RAM, a communication interface, etc.

[0118] A program that is installed in a computer and causes the computer to function as a part of the module control unit 240 according to this embodiment may include modules that define the operation of each part of the module control unit 240. These programs or modules act on a CPU or the like to cause the computer to function as each part of the module control unit 240.

[0119] The information processing described in these programs, when loaded into a computer, functions as a specific means in which the software and the various hardware resources described above work together. By using these specific means to realize calculation or processing of information according to the intended use of the computer in this embodiment, a specific device according to the intended use can be constructed. The programs may be stored in a computer-readable medium, or in a storage device connected to a network. The computer-readable medium may be a non-transitory computer-readable medium.

[0120] The protection unit 250 protects the power storage unit 210. In this embodiment, the protection unit 250 protects the power storage unit 210 from overcharging and overdischarging. When the protection unit 250 detects that the terminal voltage of the power storage cell 222 or the power storage cell 224 is not within a predetermined range, the protection unit 250 transmits a signal indicating that to the module control unit 240. The protection unit 250 may transmit information regarding the terminal voltage of the power storage unit 210 to the system control unit 140. The protection unit 250 may be realized by hardware, software, or a combination of hardware and software. The protection unit 250 may be realized by an analog circuit, a digital circuit, or a combination of an analog circuit and a digital circuit.

[0121] The balance correction unit 260 equalizes the voltages of the multiple storage cells. The operating principle of the balance correction unit 260 is not particularly limited, and any balance correction device can be used. When the power storage unit 210 has three or more storage cells, the power storage module 110 may have multiple balance correction units 260. For example, when the power storage unit 210 has n (n is an integer equal to or greater than 2) storage cells, the power storage module 110 has n-1 balance correction units 260.

[0122] The balance correction unit 260 may be realized by hardware, software, or a combination of hardware and software. The balance correction unit 260 may be realized by an analog circuit, a digital circuit, or a combination of an analog circuit and a digital circuit. In one embodiment, the balance correction unit 260 is an active type balance correction device. The active type balance correction unit may be a balance correction unit that transfers charge between two storage cells via an inductor as described in Japanese Patent Application Publication No. 2006-067742, or may be a balance correction unit that transfers charge using a capacitor as described in Japanese Patent Application Publication No. 2012-210109. In another embodiment, the balance correction unit 260 may be a passive type balance correction device. The passive type balance correction device releases excess charge using, for example, an external resistor.

[0123] In the present embodiment, the case where the power storage unit 210 has two storage cells connected in series has been described. However, the power storage unit 210 is not limited to this embodiment. In other embodiments, the power storage unit 210 may have three or more storage cells connected in series. Furthermore, the power storage unit 210 may have a plurality of storage cells connected in parallel, or a plurality of cells connected in a matrix.

[0124] The power storage unit 210 of the power storage module 110 may be an example of a second power storage unit. The switching unit 230 of the power storage module 110 may be an example of a second switching unit. The power storage cell 222 and the power storage cell 224 of the power storage module 110 may be an example of a second type of secondary battery.

[0125] 3 shows an example of a system configuration of the power storage module 130. In this embodiment, the power storage module 130 differs from the power storage module 110 in that each of the multiple power storage cells constituting the power storage unit 210 is configured with a type of secondary battery compatible with trickle charging, and in that the power storage module 130 includes a trickle charge unit 320. With respect to the configuration other than the above differences, the power storage module 130 may have similar features to the corresponding configuration of the power storage module 110.

[0126] In this embodiment, trickle charging unit 320 includes a direction restriction unit 322 and a flow rate restriction unit 324. Trickle charging unit 320 is connected in parallel with switching unit 230 between wiring 106 of power storage system 100 and power storage unit 210 of power storage module 130. Trickle charging unit 320 may have a resistance larger than that of switching unit 230. In other words, the resistance value when a current flows between wiring 106 and power storage unit 210 via trickle charging unit 320 is larger than the resistance value when a current flows via switching unit 230.

[0127] In this embodiment, trickle charging unit 320 passes a current in a direction from wiring 106 toward power storage unit 210. On the other hand, trickle charging unit 320 suppresses current from passing in a direction from power storage unit 210 toward wiring 106. For example, trickle charging unit 320 does not pass a current in a direction from power storage unit 210 toward wiring 106.

[0128] In this embodiment, the flow rate limiting unit 324 limits the amount of current flowing through the trickle charging unit 320. The flow rate limiting unit 324 may have a resistance larger than that of the switching unit 230. The flow rate limiting unit 324 may have at least one of a fixed resistor, a variable resistor, a constant current circuit, and a constant power circuit. The flow rate limiting unit 324 may have a PTC thermistor. When a current flows through the flow rate limiting unit 324 while trickle charging of the power storage unit 210 is being performed, the flow rate limiting unit 324 may generate heat. Even in this case, according to this embodiment, since the flow rate limiting unit 324 has a PTC thermistor, when the temperature of the flow rate limiting unit 324 increases, the amount of current flowing through the flow rate limiting unit 324 decreases. As a result, the temperature of the flow rate limiting unit 324 can be maintained within a predetermined numerical range while trickle charging of the power storage unit 210 is being performed.

[0129] In this embodiment, the direction restriction unit 322 is connected in series with the flow rate restriction unit 324. The direction restriction unit 322 passes a current in a direction from the wiring 106 toward the power storage unit 210. On the other hand, the direction restriction unit 322 does not pass a current in a direction from the power storage unit 210 toward the wiring 106. The direction restriction unit 322 may include a diode. The above-mentioned diode may be arranged such that the direction from the wiring 106 toward the power storage unit 210 is the forward direction.

[0130] The power storage unit 210 of the power storage module 130 may be an example of a first power storage unit. The switching unit 230 of the power storage module 130 may be an example of a first switching unit. The power storage cell 222 and the power storage cell 224 of the power storage module 130 may be an example of a first type of secondary battery. The trickle charging unit 320 may be an example of a limiting unit. The direction limiting unit 322 may be an example of a current direction limiting unit. The flow rate limiting unit 324 may be an example of a current amount limiting unit.

[0131] 4 shows an example of a system configuration of the module control unit 240. In this embodiment, the module control unit 240 includes a determination unit 410, a receiving unit 420, and a signal generation unit 430. The module control unit 240 may include a module information acquisition unit 440, a module information storage unit 450, and a module information transmission unit 460. The receiving unit 420 may be an example of a first signal receiving unit, a second signal receiving unit, and a third signal receiving unit. The module information acquisition unit 440 may be an example of a battery characteristic acquisition unit.

[0132] In this embodiment, a case will be described in which the module control unit 240 includes a module information acquisition unit 440, a module information storage unit 450, and a module information transmission unit 460. However, the power storage system 100 is not limited to this embodiment. In other embodiments, the system control unit 140 may include at least one of the module information acquisition unit 440, the module information storage unit 450, and the module information transmission unit 460.

[0133] The determination unit 410 determines whether or not the voltage between the terminals of the switching unit 230 is within a predetermined range. The determination unit 410 transmits a signal indicating the determination result to the signal generating unit 430. The determination unit 410 may be any comparator or comparison circuit. The determination unit 410 may be a window comparator.

[0134] The receiving unit 420 receives at least one of a signal from the system control unit 140, a signal from the protection unit 250, and an instruction from a user. The receiving unit 420 transmits to the signal generating unit 430 a signal corresponding to the received information.

[0135] The signal generating unit 430 receives a signal from at least one of the determining unit 410 and the receiving unit 420. The signal generating unit 430 generates a signal for controlling the switching unit 230 based on the received information. The signal generating unit 430 transmits the generated signal to the switching unit 230.

[0136] In one embodiment, when the determination unit 410 determines that the terminal voltage of the switching unit 230 is within a predetermined range, the signal generation unit 430 generates a signal for turning on the switching element of the switching unit 230. In another embodiment, when the determination unit 410 determines that the terminal voltage of the switching unit 230 is not within the predetermined range, the signal generation unit 430 generates a signal for turning off the switching element of the switching unit 230.

[0137] The signal generating unit 430 may generate or transmit the signal after a predetermined time has elapsed since the determining unit 410 determined whether or not the inter-terminal voltage of the switching unit 230 is within a predetermined range. This makes it possible to prevent malfunctions due to noise and the like. Also, it is possible to prevent the power storage unit 210 and the wiring 106 from being electrically connected to each other immediately after the power storage module 110 is mounted in the power storage system 100.

[0138] In this embodiment, the signal generating unit 430 generates a signal for controlling the switching element of the switching unit 230 based on the signal received by the receiving unit 420. In one embodiment, when the receiving unit 420 receives a signal for turning on the switching element of the switching unit 230 from the system control unit 140, the signal generating unit 430 generates a signal for turning on the switching element of the switching unit 230.

[0139] In another embodiment, when the receiving unit 420 receives a signal for turning off the switching element of the switching unit 230 from the protection unit 250, the signal generating unit 430 generates a signal for turning off the switching element of the switching unit 230. In yet another embodiment, when the receiving unit 420 accepts an instruction from a user, the signal generating unit 430 generates a signal for operating the switching element of the switching unit 230 according to the instruction from the user.

[0140] In this embodiment, the module information acquiring unit 440 acquires information on the battery characteristics of the power storage unit 210. The module information acquiring unit 440 may acquire information on the battery characteristics of the power storage unit 210 by measuring the battery characteristics of the power storage unit 210. The module information acquiring unit 440 may acquire information on the battery characteristics of the power storage unit 210 input by a manufacturer, a seller, or the like at the time of shipment, inspection, or sale.

[0141] The module information acquisition unit 440 may store information relating to the battery characteristics of the power storage unit 210 in the module information storage unit 450. The specific configuration of the module information acquisition unit 440 is not particularly limited, but the module information acquisition unit 440 may be a controller that controls reading and writing of data in the module information storage unit 450. In this embodiment, the module information storage unit 450 stores the information relating to the battery characteristics of the power storage unit 210 acquired by the module information acquisition unit 440.

[0142] In this embodiment, the module information transmission unit 460 transmits information on the battery characteristics of the power storage unit 210 acquired by the module information acquisition unit 440 to the system control unit 140. The module information transmission unit 460 may transmit information on the battery characteristics of the power storage unit 210 acquired by the module information acquisition unit 440 to an external device. The module information transmission unit 460 may transmit information on the battery characteristics of the power storage unit 210 in response to a request from the external device, or may transmit information on the battery characteristics of the power storage unit 210 at a predetermined timing. The module information transmission unit 460 may transmit information on the battery characteristics of the power storage unit 210 to the system control unit 140 or an external device by referring to the module information storage unit 450.

[0143] Fig. 5 shows an example of a schematic circuit configuration of the power storage module 110. For the purpose of simplifying the explanation, the protection unit 250 and wiring related to the protection unit 250 are not shown in Fig. 5.

[0144] In this embodiment, the switching unit 230 includes a transistor 510, a resistor 512, a resistor 514, a diode 516, a transistor 520, a resistor 522, a resistor 524, and a diode 526. The transistor 510 and the transistor 520 may be an example of a switching element. In this embodiment, a case where the transistor 510 and the transistor 520 are used as the switching elements of the switching unit 230 will be described. However, the switching elements of the switching unit 230 are not limited to this embodiment. In other embodiments, a single switching element may be used as the switching element of the switching unit 230.

[0145] In this embodiment, the module control unit 240 includes a determination unit 410, a signal generation unit 430, a switch 592, and a switch 594. In this embodiment, the determination unit 410 includes a transistor 530, a resistor 532, a transistor 540, a resistor 542, a resistor 552, and a resistor 554. The signal generation unit 430 includes a transistor 560, a capacitor 570, a resistor 572, and a transistor 580. The switch 592 and the switch 594 may be an example of the receiving unit 420.

[0146] Next, the details of each part of the switching unit 230 and the module control unit 240 will be described. In the switching unit 230 of this embodiment, the transistor 510 is a MOSFET, and even when the transistor 510 is off, a current can flow from the positive terminal 212 to the positive terminal 202 due to a parasitic diode (not shown) equivalently formed between the source and drain of the transistor 510. Similarly, the transistor 520 is a MOSFET, and even when the transistor 520 is off, a current can flow from the positive terminal 202 to the positive terminal 212 due to a parasitic diode (not shown) equivalently formed between the source and drain of the transistor 520.

[0147] In this embodiment, the transistor 510 and the transistor 520 are initially set to off. When the transistor 580 is turned on during charging of the power storage system 100, a current flows from the positive electrode terminal 202 to the negative electrode terminal 204 via the resistor 512, the resistor 514, and the transistor 580. As a result, a voltage is applied to the gate of the transistor 510, and the transistor 510 is turned on. This allows a current to flow from the positive electrode terminal 202 to the positive electrode terminal 212 via a parasitic diode equivalently formed between the source and drain of the transistor 520.

[0148] On the other hand, when the power storage system 100 is discharged and the transistor 580 is turned on, a current flows from the positive electrode terminal 212 to the negative electrode terminal 214 via the resistor 522, the resistor 524, and the transistor 580. As a result, a voltage is applied to the gate of the transistor 520, and the transistor 520 is turned on. This allows a current to flow from the positive electrode terminal 212 to the positive electrode terminal 202 via a parasitic diode equivalently formed between the source and drain of the transistor 510.

[0149] The voltage applied to the gate of the transistor 510 or the transistor 520 as the transistor 580 turns on may be an example of a signal for turning on the switching element of the switching unit 230. Similarly, the voltage applied to the gate of the transistor 510 or the transistor 520 as the transistor 580 turns off may be an example of a signal for turning off the switching element of the switching unit 230.

[0150] In this embodiment, the values ​​of resistors 512 and 514 are set so that transistor 510 can be reliably turned on / off with reduced power consumption. Also, the values ​​of resistors 522 and 524 are set so that transistor 520 can be reliably turned on / off with reduced power consumption.

[0151] In this embodiment, a diode 516 is disposed between the resistor 514 and the resistor 524. The diode 516 allows a current to pass in a direction from the resistor 514 to the resistor 524, but does not allow a current to pass in a direction from the resistor 524 to the resistor 514. By providing the diode 516, it is possible to prevent a current from leaking from the positive terminal 212 to the positive terminal 202 through the route of the resistor 522, the resistor 524, the resistor 514, and the resistor 512 when the switching unit 230 electrically disconnects the positive terminal 202 from the positive terminal 212.

[0152] In this embodiment, a diode 526 is disposed between the resistor 514 and the resistor 524. The diode 526 allows a current to pass in a direction from the resistor 524 to the resistor 514, but does not allow a current to pass in a direction from the resistor 514 to the resistor 524. By providing the diode 526, it is possible to prevent a current from leaking from the positive terminal 202 to the positive terminal 212 through the route of the resistor 512, the resistor 514, the resistor 524, and the resistor 522 when the switching unit 230 electrically disconnects the positive terminal 202 from the positive terminal 212.

[0153] In the module control unit 240 of this embodiment, the transistors 530 and 540 of the determination unit 410 are initially set to off, and the transistors 560 and 580 of the signal generation unit 430 are initially set to off.

[0154] According to this embodiment, the value of the resistor 532 is set so that the transistor 530 is turned on when the terminal voltage of the switching unit 230 is smaller than a predetermined first value with the positive terminal 202 side being positive. The value of the resistor 532 is preferably set so that the current leaking when the switching unit 230 is off is minimized. The value of the resistor 542 is set so that the transistor 540 is turned on when the terminal voltage of the switching unit 230 is larger than a predetermined second value. The value of the resistor 542 is preferably set so that the current leaking when the switching unit 230 is off is minimized. Note that, according to this embodiment, the terminal voltage of the switching unit 230 is equal to the voltage difference between the positive terminal 202 and the positive terminal 212.

[0155] When the terminal voltage of the switching unit 230 is smaller than a predetermined first value, the transistor 530 is turned on, and a voltage is applied from the power storage unit 210 to the base of the transistor 560 via the positive terminal 212, the transistor 530, and the resistor 552, and the transistor 560 is turned on. Although the voltage from the positive terminal 202 is applied to the base of the transistor 580, the transistor 580 is prevented from being turned on while the transistor 560 is in the on-state. As a result, the transistor 580 is turned off.

[0156] On the other hand, when the inter-terminal voltage of the switching unit 230 is greater than a predetermined second value, the transistor 540 is turned on, and a voltage is applied from the positive terminal 202 to the base of the transistor 560 via the transistor 540 and the resistor 554, turning on the transistor 560. As a result, the transistor 580 is turned off.

[0157] In this embodiment, the value of resistor 552 is set so as to reduce power consumption to the extent that transistor 560 can be turned on when transistor 530 is on. The value of resistor 554 is set so as to reduce power consumption to the extent that transistor 560 can be turned on when transistor 540 is on.

[0158] The capacitance of capacitor 570 is set so that transistor 560 turns on before transistor 580 turns on when a voltage from positive terminal 202 is applied to the base of transistor 580. This allows signal generating unit 430 to generate a signal after a predetermined time has elapsed since determining unit 410 determined whether or not the voltage between the terminals of the switching element is within a predetermined range.

[0159] On the other hand, when the terminal voltage of the switching unit 230 is within the range determined by the first value and the second value, the transistors 530 and 540 remain off, and the transistor 560 also remains off. Therefore, a voltage is applied from the positive terminal 202 to the base of the transistor 580 via the resistor 572, and the transistor 580 turns on.

[0160] The switches 592 and 594 may be manual switches, or may be switching elements such as relays, thyristors, transistors, etc. A signal 52 indicating that the switching unit 230 is to be turned on may be input to the switch 592. A signal 54 indicating that the switching unit 230 is to be turned off may be input to the switch 594.

[0161] When the switch 592 is turned on, the switching unit 230 can be turned on regardless of whether the transistor 580 is on or off. When the switch 594 is turned on, the transistor 580 can be turned off regardless of whether the transistor 560 is on or off. As a result, the switching unit 230 can be turned off.

[0162] Fig. 6 shows an example of a system configuration of the system control unit 140. An overview of information processing between the charging device 14, the load device 20, and the system control unit 140 will be described with reference to Fig. 6. In this embodiment, the system control unit 140 includes a state management unit 622, a module selection unit 624, and a signal generation unit 626. In this embodiment, the charging device 14 includes a charge switching unit 16, a charge control unit 642, and a charging unit 644. In this embodiment, the load device 20 includes a load switching unit 26, a load control unit 662, and a load unit 664.

[0163] [Overview of each part of the system control unit 140] In this embodiment, the state management unit 622 manages the state of the power storage system 100. The state management unit 622 may manage the states of the power storage module 110 and the power storage module 130. The state management unit 622 may monitor the states of the power storage module 110 and the power storage module 130. The state management unit 622 may monitor the power storage module 110 and the power storage module 130 to obtain information on the battery characteristics of the power storage module 110 and the power storage module 130. The state management unit 622 may transmit the information obtained by monitoring the power storage module 110 and the power storage module 130 to an external device.

[0164] The state management unit 622 may measure the battery characteristics of each power storage module while operating the power storage system 100. When the battery characteristics of a power storage module do not satisfy a predetermined condition, the state management unit 622 may output information indicating that the performance of the power storage module is insufficient to an output device that outputs information to a user. The state management unit 622 may output identification information of the power storage module and information indicating that the performance of the power storage module is insufficient.

[0165] This allows the user to easily identify an energy storage module with insufficient performance and replace the energy storage module. According to the present embodiment, for example, in the case of constructing the energy storage system 100 using a reused energy storage module, it is possible to omit at least a part of the inspection of the reused energy storage module.

[0166] In one embodiment, when the power storage system 100 transitions to a charging state, the module selection unit 624 selects a storage module having the smallest terminal voltage from among the multiple power storage modules included in the power storage system 100. For example, the module selection unit 624 compares the terminal voltages of the power storage module 110 and the power storage module 130, and selects the storage module having the smaller terminal voltage. The module selection unit 624 transmits a signal indicating the selected power storage module to the signal generation unit 626.

[0167] In another embodiment, when the power storage system 100 transitions to a discharging state, the module selection unit 624 selects a power storage module having the largest terminal voltage among the multiple power storage modules included in the power storage system 100. For example, the module selection unit 624 compares the terminal voltages of the power storage module 110 and the power storage module 130, and selects the power storage module having the larger terminal voltage. The module selection unit 624 transmits a signal indicating the selected power storage module to the signal generation unit 626.

[0168] In this embodiment, the signal generating unit 626 generates a signal for turning on the switching element of the switching unit 230 of the power storage module selected by the module selecting unit 624. The signal generating unit 626 transmits the generated signal to the module control unit 240. In another embodiment, the signal generating unit 626 may generate a signal for turning off the switching element of the switching unit 230 of the power storage module selected by the module selecting unit 624.

[0169] In the present embodiment, the signal generating unit 626 may generate a signal for controlling the charging device 14. For example, the signal generating unit 626 generates a signal for adjusting at least one of the set values ​​of the charging voltage and the charging current of the charging device 14. The signal generating unit 626 may transmit a signal for controlling the charging device 14 to the charging device 14. In this way, charging of the power storage system 100 is controlled.

[0170] In this embodiment, the signal generating unit 626 generates a signal for setting the charging voltage of the charging device 14. For example, the signal generating unit 626 acquires information on the battery characteristics of each storage module attached to the power storage system 100 from the state managing unit 622. Based on the information on the battery characteristics, the signal generating unit 626 identifies the storage module with the highest charging end voltage among the storage modules attached to the power storage system 100. Based on the information on the battery characteristics, the signal generating unit 626 determines whether the storage module with the highest charging end voltage supports trickle charging.

[0171] When the storage module with the highest charging end voltage supports trickle charging, the signal generating unit 626 may generate a signal for setting the charging voltage of the charging device 14 to a value equal to or greater than the full charging voltage of the storage module. On the other hand, when the storage module with the highest charging end voltage does not support trickle charging, the signal generating unit 626 may generate a signal for setting the charging voltage of the charging device 14 to a value equal to or greater than the charging end voltage of the storage module.

[0172] As described above, even if the energy storage modules mounted in the energy storage system 100 include a storage module capable of trickle charging, whether trickle charging can be performed may depend on the specifications of the other energy storage modules. However, according to the present embodiment, when the energy storage modules mounted in the energy storage system 100 include a storage module capable of trickle charging, trickle charging of the storage module can be reliably performed.

[0173] In the present embodiment, the signal generating unit 626 may generate a signal for controlling the operation of the charge switching unit 16. The signal generating unit 626 may transmit a signal for controlling the operation of the charge switching unit 16 to the charging device 14 or the charge switching unit 16. For example, the signal generating unit 626 generates a signal for controlling the ON / OFF operation of the charge switching unit 16. This switches, for example, the electrical connection relationship between the charging device 14 and the power storage system 100. When the charge switching unit 16 has a function of adjusting the amount of current, the signal generating unit 626 may generate a signal for controlling the amount of current of the charging current. This allows the amount of current of the charging current to be controlled. Details of the control of the operation of the charge switching unit 16 will be described later.

[0174] In the present embodiment, the signal generating unit 626 may generate a signal for controlling the load device 20. For example, the signal generating unit 626 may generate a signal for adjusting a set value of a current consumption of the load device 20. In this way, the discharge of the power storage system 100 is controlled.

[0175] For example, the signal generating unit 626 generates a signal for controlling the load device 20 so that the current consumption of the load device 20 increases continuously or stepwise after the power storage system 100 supplies power to the load device 20. This allows the increase speed of the output current supplied from the power supply system 10 to the load device 20 to be controlled.

[0176] In the power storage system 100 according to this embodiment, if the rate at which the voltage of the wiring 106 (which may be referred to as line voltage, output voltage, etc.) decreases is greater than the operating speed of the switching unit 230, the power storage module mounted in the power storage system 100 cannot be connected to the wiring 106, and the power supply of the power supply system 10 may become unstable. However, by controlling the rate at which the output current supplied from the power supply system 10 to the load device 20 increases within a range that the switching unit 230 can handle, the power supply system 10 can stably supply power.

[0177] In the present embodiment, the signal generating unit 626 may generate a signal for controlling the operation of the load switching unit 26. The signal generating unit 626 may transmit a signal for controlling the operation of the load switching unit 26 to the load device 20 or the load switching unit 26. For example, the signal generating unit 626 generates a signal for controlling the ON / OFF operation of the load switching unit 26. This switches the electrical connection between the load device 20 and the power storage system 100. When the load switching unit 26 has a function of adjusting the amount of current, the signal generating unit 626 may generate a signal for controlling the amount of current of the load switching unit 26. This allows the amount of discharge current (sometimes referred to as output current) to be controlled. Details of the control of the operation of the load switching unit 26 will be described later.

[0178] In this embodiment, the signal generating unit 626 may generate a signal for controlling the operation of an element or circuit (not shown) for controlling at least one of the output voltage and the output current provided in the power storage system 100. The signal generating unit 626 may transmit the above signal to the above element or circuit. For example, the signal generating unit 626 generates a signal for controlling the magnitude of at least one of the output voltage and the output current supplied from the power supply system 10 to the load device 20.

[0179] In one embodiment, the signal generating unit 626 receives a signal (sometimes referred to as a request signal) from the load device 20 indicating the magnitude of a current to be supplied to the load device 20. The signal generating unit 626 generates a signal for controlling the operation of the above-mentioned element or circuit so that a current of the magnitude indicated by the request signal is output. This allows the output current supplied from the power supply system 10 to the load device 20 to be controlled. In another embodiment, the signal generating unit 626 may generate a signal for controlling the magnitude of the output current so that the output current increases continuously or stepwise after the power storage system 100 starts supplying power. This allows the output current supplied from the power supply system 10 to the load device 20 to be controlled.

[0180] In this embodiment, the signal generating unit 626 may generate a signal for controlling each power storage module of the power storage system 100. The signal generating unit 626 may transmit the signal to the power storage module that is to be controlled by the signal. For example, the signal generating unit 626 generates a signal to notify the load device 20 that it will operate. The signal generating unit 626 may also generate a signal to notify the load device 20 that it is already operating.

[0181] [Overview of each part of the charging device 14] In this embodiment, the charging control unit 642 controls the charging unit 644. Specifically, the charging control unit 642 controls the magnitude of at least one of the voltage (sometimes referred to as charging voltage) and the current (sometimes referred to as charging current) output by the charging unit 644. The charging control unit 642 may control the rate of change of at least one of the charging voltage and the charging current.

[0182] The charging control unit 642 may receive a signal from the signal generating unit 626 of the system control unit 140, and based on the signal, control the charging unit 644. The charging control unit 642 may control the charging unit 644 according to an instruction input by a user to an input device (not shown).

[0183] The charging control unit 642 may control the set value of the charging voltage of the charging unit 644. For example, the charging control unit 642 adjusts the set value of the charging voltage so that the charging voltage of the charging device 14 is higher than the full charge voltage of the storage module 130. As a result, the full charge voltage of the storage module 130 becomes lower than the charging voltage of the charging device 14. As described above, in this embodiment, the storage unit 210 of the storage module 130 supports trickle charging. In addition, the charging end voltage of the storage module 130 is the highest among the multiple storage modules attached to the storage system 100. Even in such a case, by setting the charging voltage of the charging device 14 as described above, the full charge voltage of the storage module 130 can be maintained by trickle charging after the voltage of the storage module 130 reaches the charging end voltage.

[0184] The charging control unit 642 may control the charging method of the charging unit 644. Examples of the charging method include a constant voltage charging method, a constant current charging method, a constant voltage constant current charging method, and a trickle charging method.

[0185] For example, the charging control unit 642 controls the charging unit 644 so that both the storage modules 110 and 130 are charged by a constant current charging method during at least a part of the charging period of the storage modules 110 and 130. Thereafter, the charging control unit 642 may control the charging unit 644 so that the storage module 130 is charged by a constant voltage charging method. For example, after the charging of the storage module 110 is completed, the charging control unit 642 may control the charging unit 644 so that the storage module 130 is charged by a constant voltage charging method. Furthermore, after the voltage of the storage module 130 reaches the charging end voltage of the storage module 130, the charging control unit 642 may control the charging unit 644 so that the storage module 130 is charged by a trickle charging method.

[0186] As a result, when the voltage of the power storage module 130 is equal to or lower than the charging end voltage, the charging device 14 charges the power storage module 130 by a constant current charging method or a constant voltage charging method. Also, when the voltage of the power storage module 130 is higher than the charging end voltage, the charging device 14 charges the power storage module 130 by a trickle charging method.

[0187] In this embodiment, the charging unit 644 receives power from a system power supply. The charging unit 644 also supplies power to the power storage system 100 via the charging switching unit 16. The charging unit 644 may output power at a current having a magnitude set by the charging control unit 642. The charging unit 644 may output power at a voltage having a magnitude set by the charging control unit 642.

[0188] [Overview of each part of the load device 20] In this embodiment, the load control unit 662 controls the load unit 664. Specifically, the load control unit 662 controls at least one of the magnitudes of the voltage (sometimes referred to as consumption voltage) and current (sometimes referred to as consumption current) of the power consumed by the load unit 664. The load control unit 662 may control the rate of change of at least one of the consumption voltage and consumption current. For example, the load control unit 662 controls the load unit 664 so that the consumption current of the load device 20 increases continuously or stepwise after the power storage system 100 supplies power to the load device 20.

[0189] The load control unit 662 may receive a signal from the signal generating unit 626 of the system control unit 140 and control the load unit 664 based on the signal. The load control unit 662 may control the load unit 664 according to an instruction input by a user to an input device (not shown).

[0190] The charge control unit 642 may be an example of a charge voltage control unit. The load control unit 662 may be an example of a current consumption control unit.

[0191] An outline of the charging operation of the power storage system 100 will be described with reference to Fig. 7, Fig. 8, and Fig. 9. Fig. 7 shows an example of a fluctuation 730 in the terminal voltage of the power storage module 130 and an example of a fluctuation 710 in the terminal voltage of the power storage module 110 during the charging period of the power storage module 110 and the power storage module 130. Fig. 7 also shows an example of a fluctuation 740 in the current passing through the power storage unit 210 of the power storage module 130. Fig. 8 shows an example of a fluctuation 814 in the charging voltage of the charging device 14. Fig. 9 shows an example of an output characteristic 914 of the charging device 14.

[0192] 7, according to this embodiment, charging of the power storage system 100 starts at time t1. The maximum value of the charging voltage of the charging device 14 is set to Vcv. At the time t1 when charging of the power storage system 100 starts, the inter-terminal voltages of the power storage module 110 and the power storage module 130 are Vai and Vbi, respectively. At this time, the power storage unit 210 and the wiring 106 of the power storage module 110 are electrically connected, and the power storage unit 210 and the wiring 106 of the power storage module 130 are electrically disconnected.

[0193] Thereafter, charging of the power storage module 110 progresses, and at time t2 the inter-terminal voltage of the power storage module 110 reaches Vai, at which point the switching unit 230 of the power storage module 130 turns ON, and the power storage unit 210 of the power storage module 130 and the wiring 106 are electrically connected.

[0194] Thereafter, charging of the storage module 110 and the storage module 130 progresses, and at time t3, when the terminal voltage of the storage module 110 reaches the charging termination voltage Vbc of the storage module 110, the protection unit 250 of the storage module 110 detects overcharging and controls the switching unit 230, thereby electrically disconnecting the storage unit 210 and the wiring 106 of the storage module 110.

[0195] Thereafter, charging of the power storage module 130 progresses, and at time t4, when the terminal voltage of the power storage module 130 reaches the charging end voltage Vac of the power storage module 130, the protection unit 250 of the power storage module 110 detects overcharging and controls the switching unit 230. As a result, the power storage unit 210 and the wiring 106 of the power storage module 130 are electrically disconnected.

[0196] At this time, as shown in Fig. 8, the power storage unit 210 of the power storage module 130 and the wiring 106 are electrically disconnected, and the voltage of the wiring 106 becomes equal to the output voltage Vcv of the charging device 14. In addition, as shown in Fig. 9, the charging current decreases rapidly due to the power storage unit 210 of the power storage module 130 and the wiring 106 being electrically disconnected.

[0197] Thereafter, trickle charging is performed on the power storage module 130. As a result, the terminal voltage of the power storage module 130 reaches the fully charged voltage Vaf of the power storage module 130. Furthermore, trickle charging maintains the power storage module 130 in a fully charged state.

[0198] The charging operation described with reference to Figures 7, 8, and 9 may be controlled by the charging control unit 642. The charging operation described with reference to Figures 7, 8, and 9 may be performed by the system control unit 140 controlling the charging control unit 642.

[0199] [Electricity storage module with interlock mechanism] Next, other examples of the power storage module 110 will be described with reference to Figs. 10, 11, and 12. To the extent that there is no technical contradiction, the matters described for the power storage module 110 and each part thereof may be applied to other examples of the power storage module 110 and each part thereof. Furthermore, the matters described for the other examples of the power storage module 110 and each part thereof may be applied to the power storage module 110 and each part thereof. In the description of Figs. 10 to 12, the matters described for each part of the power storage module 110 may be omitted.

[0200] 10 illustrates an example of a system configuration of a power storage module 1010. In this embodiment, the power storage module 1010 includes a positive terminal 202, a negative terminal 204, and a power storage unit 210. The power storage module 1010 may include a switching unit 230. The power storage module 1010 may include a protection unit 250. The power storage module 1010 may include a balance correction unit 260. In this embodiment, the power storage module 1010 includes a current detection element 1020 and a module control unit 1040.

[0201] In this embodiment, the switching unit 230 adjusts the current flowing between the wiring 106 and the power storage unit 210. In one embodiment, the switching unit 230 electrically connects the wiring 106 and the power storage unit 210, or electrically disconnects the wiring 106 and the power storage unit 210. In another embodiment, the switching unit 230 increases or decreases the above-mentioned current by, for example, changing the resistance value of the path between the wiring 106 and the power storage unit 210.

[0202] In this embodiment, one end of the switching unit 230 is electrically connected to the wiring 106 via the positive terminal 202 and the current detection element 1020. The other end of the switching unit 230 is electrically connected to the positive terminal 212 of the power storage unit 210. Information indicating the terminal-to-terminal voltage of the switching unit 230 may be used as information indicating a difference between the potential of the wiring 106 or the voltage applied to the wiring 106 (which may be simply referred to as the voltage of the wiring 106) and the potential of a terminal (for example, the positive terminal 212) of the power storage unit 210 or the voltage applied to the terminal (which may be simply referred to as the voltage of the power storage unit 210, the voltage of the terminal, etc.).

[0203] In one embodiment, the switching unit 230 adjusts the magnitude of a current flowing at least between the wiring 106 and the power storage unit 210 in a direction from the positive electrode terminal 212 of the power storage unit 210 toward the positive electrode terminal 202 of the power storage unit 210 (sometimes referred to as a discharging direction). In another embodiment, the switching unit 230 adjusts the magnitude of a current flowing at least between the wiring 106 and the power storage unit 210 in a direction from the positive electrode terminal 202 toward the positive electrode terminal 212 of the power storage unit 210 (sometimes referred to as a charging direction). In yet another embodiment, the switching unit 230 adjusts the magnitude of a current flowing between the wiring 106 and the power storage unit 210 in a discharging direction and a current flowing between the wiring 106 and the power storage unit 210 in a charging direction.

[0204] In this embodiment, the power storage module 1010 differs from the power storage module 110 in that it includes a current detection element 1020. The power storage module 1010 differs from the power storage module 110 in that it includes a module control unit 1040 instead of the module control unit 240. Regarding configurations other than the above differences, the power storage module 1010 may have similar features to the corresponding configurations of the power storage module 110.

[0205] In this embodiment, the current detection element 1020 is used to obtain information indicating the current flowing between the wiring 106 and the power storage unit 210. Examples of the information indicating the current include the presence or absence of the current, the magnitude of the current, and the direction of the current. In this embodiment, the power storage module 1010 obtains information regarding the current flowing between the wiring 106 and the power storage unit 210 by measuring the voltage between the terminals of the current detection element 1020.

[0206] In this embodiment, the current detection element 1020 is disposed between the positive electrode terminal 202 and the switching unit 230. More specifically, one end of the current detection element 1020 is electrically connected to the switching unit 230. The other end of the current detection element 1020 is electrically connected to the wiring 106 via the positive electrode terminal 202. The current detection element 1020 may be disposed between the switching unit 230 and the positive electrode terminal 212 of the power storage unit 210. The switching unit 230 or a part of the elements constituting the switching unit 230 may be used as the current detection element 1020.

[0207] The current detection element 1020 may be an element having any resistance value, and the type is not particularly limited. For example, the current detection element 1020 has an appropriate resistance value according to the maximum allowable current of the power storage unit 210. Examples of the current detection element 1020 include a resistor and a Hall sensor. A passive element or an active element having an appropriate resistance value may be used as the resistor.

[0208] In this embodiment, the module control unit 1040 differs from the module control unit 240 in that it detects a current flowing between the wiring 106 and the power storage unit 210. In this embodiment, the module control unit 1040 differs from the module control unit 240 in that it controls the operation of the switching unit 230 based on (i) the voltage or SOC of the power storage unit 210, and (ii) the current flowing between the wiring 106 and the power storage unit 210. The module control unit 1040 may control the operation of the switching unit 230 based on (i) the voltage or SOC of the power storage unit 210, (ii) the current flowing between the wiring 106 and the power storage unit 210, and (iii) the voltage between the terminals of the switching unit 230. Regarding the configuration other than the above differences, the module control unit 1040 may have the same characteristics as the corresponding configuration of the module control unit 240.

[0209] There is no particular limitation on the method by which the module control unit 1040 detects the current flowing between the wiring 106 and the power storage unit 210. In this embodiment, the module control unit 1040 acquires information indicating the inter-terminal voltage of the current detection element 1020 disposed between the positive terminal 202 and the positive terminal 212, and detects the current flowing between the wiring 106 and the power storage unit 210 based on the information. This allows the module control unit 1040 to monitor the current flowing between the wiring 106 and the power storage unit 210. The module control unit 1040 may determine the magnitude of the current flowing between the wiring 106 and the power storage unit 210, and may also determine the direction of the current.

[0210] In one embodiment, when the switching unit 230 adjusts or controls at least the magnitude of the current flowing in the discharging direction between the wiring 106 and the power storage unit 210, the module control unit 1040 monitors or detects the current flowing in the charging direction between the wiring 106 and the power storage unit 210. When the switching unit 230 cuts off the electrical connection between the wiring 106 and the power storage unit 210 in the discharging direction (sometimes referred to as "electrically cutting in the discharging direction"), the module control unit 1040 may monitor or detect the current flowing between the wiring 106 and the power storage unit 210. Note that in this case, the current detected by the module control unit 1040 is, as a result, the current flowing in the charging direction between the wiring 106 and the power storage unit 210.

[0211] In another embodiment, when the switching unit 230 adjusts or controls at least the magnitude of the current flowing in the charging direction between the wiring 106 and the power storage unit 210, the module control unit 1040 monitors or detects the current flowing in the discharging direction between the wiring 106 and the power storage unit 210. When the switching unit 230 cuts off the electrical connection in the charging direction between the wiring 106 and the power storage unit 210 (sometimes referred to as "electrically cutting in the charging direction"), the module control unit 1040 may monitor or detect the current flowing between the wiring 106 and the power storage unit 210. Note that in this case, the current detected by the module control unit 1040 is, as a result, the current flowing in the discharging direction between the wiring 106 and the power storage unit 210.

[0212] There is no particular limitation on the method by which the module control unit 1040 controls the operation of the switching unit 230. As described above, the module control unit 1040 detects the current flowing between the wiring 106 and the power storage unit 210. The module control unit 1040 may control the operation of the switching unit 230 based on information indicating the current flowing between the wiring 106 and the power storage unit 210. This makes it possible to safely release the interlock of the switching unit 230 when hot-plugging and inserting the power storage module 1010.

[0213] Like the module control unit 240, the module control unit 1040 may acquire information indicating the terminal voltage of the switching unit 230. The module control unit 1040 may control the operation of the switching unit 230 based on the information indicating the terminal voltage of the switching unit 230. This reduces the time required for hot insertion / removal of the power storage module 1010.

[0214] Similarly to the module control unit 240, the module control unit 1040 may acquire information acquired or generated by the protection unit 250 from the protection unit 250. For example, the module control unit 1040 acquires from the protection unit 250 information indicating that the overcharge protection function is enabled, information indicating that the overcharge protection function is not enabled, information indicating that the overdischarge protection function is enabled, information indicating that the overdischarge protection function is not enabled, and the like. The module control unit 1040 may control the operation of the switching unit 230 based on the information acquired or generated by the protection unit 250. This makes it possible to appropriately control the switching unit 230 depending on the state of the power storage unit 210.

[0215] For example, when the voltage or SOC of the power storage unit 210 is smaller than or equal to the threshold for overdischarge protection, the overdischarge protection function is enabled. When the voltage or SOC of the power storage unit 210 is larger than or equal to the threshold for overdischarge protection, the overdischarge protection function is disabled. Also, for example, when the voltage or SOC of the power storage unit 210 is larger than or equal to the threshold for overcharge protection, the overcharge protection function is enabled. When the voltage or SOC of the power storage unit 210 is smaller than or equal to the threshold for overcharge protection, the overcharge protection function is disabled.

[0216] Like the module control unit 240, the module control unit 1040 may acquire information acquired or generated by the system control unit 140 from the system control unit 140. For example, the module control unit 1040 acquires information indicating the battery characteristics of the power storage unit 210 from the system control unit 140. The module control unit 1040 may control the operation of the switching unit 230 based on the information acquired or generated by the system control unit 140. This makes it possible to appropriately control the switching unit 230 depending on the state of the power storage unit 210.

[0217] [Specific Example of Procedure for Controlling Operation of Switching Unit 230] In one embodiment, the module control unit 1040 controls the operation of the switching unit 230 based on the charge state of the power storage unit 210. In another embodiment, the module control unit 1040 controls the operation of the switching unit 230 based on the voltage between the terminals of the switching unit 230. In yet another embodiment, the module control unit 1040 controls the operation of the switching unit 230 based on a current flowing between the wiring 106 and the power storage unit 210. The module control unit 1040 may control the operation of the switching unit 230 based on at least one of the magnitude and direction of the above-mentioned current.

[0218] More specifically, the module control unit 1040 controls the operation of the switching unit 230 based on (i) the voltage or SOC of the power storage unit 210, and (ii) the current flowing between the wiring 106 and the power storage unit 210. The module control unit 1040 may control the operation of the switching unit 230 based on (i) the voltage or SOC of the power storage unit 210, (ii) the current flowing between the wiring 106 and the power storage unit 210, and (iii) the voltage between the terminals of the switching unit 230.

[0219] For example, when the voltage or SOC of the power storage unit 210 satisfies a predetermined condition, the module control unit 1040 controls the switching unit 230 so that the switching unit 230 electrically connects the wiring 106 and the power storage unit 210. The battery characteristics of the power storage unit 210, such as the voltage or SOC of the power storage unit 210, may be an example of the battery characteristics of the power storage unit 210. The predetermined condition may be a condition using a predetermined numerical range or threshold, or may be a condition using a numerical range or threshold calculated according to a predetermined procedure. This makes it possible to prevent, for example, deterioration or damage of the power storage unit 210 due to overcharging or overdischarging.

[0220] The predetermined condition may be a condition for protecting the power storage unit 210. Examples of the predetermined condition include (i) a condition indicating that the voltage or SOC of the power storage unit 210 is within a specific numerical range, (ii) a condition indicating that the voltage or SOC of the power storage unit 210 is greater than a specific threshold value or is equal to or greater than a specific threshold value, (iii) a condition indicating that the voltage or SOC of the power storage unit 210 is less than a specific threshold value or is equal to or less than a specific threshold value, and (v) a combination of these conditions.

[0221] The condition indicating that the voltage or SOC of the power storage unit 210 is within a specific numerical range may be a condition indicating that at least one of the overvoltage protection function and the overdischarge protection function of the power storage module 1010 is not enabled. The condition indicating that the voltage or SOC of the power storage unit 210 is within a specific numerical range may be a condition indicating that the overvoltage protection function and the overdischarge protection function of the power storage module 1010 are not enabled. The condition indicating that the voltage or SOC of the power storage unit 210 is greater than a specific threshold value or is equal to or greater than a specific threshold value may be a condition indicating that the overdischarge protection function of the power storage module 1010 is not enabled. The condition indicating that the voltage or SOC of the power storage unit 210 is less than a specific threshold value or is equal to or less than a specific threshold value may be a condition indicating that the overcharge protection function of the power storage module 1010 is not enabled.

[0222] According to this embodiment, the module control unit 1040 controls the switching unit 230 so that, when the voltage between the terminals of the switching unit 230 satisfies a predetermined condition, the switching unit 230 electrically connects the power storage unit 210 and the wiring 106. More specifically, when the difference between the voltage of the wiring 106 and the voltage of the power storage unit 210 is relatively large, the power storage unit 210 and the wiring 106 are electrically disconnected. On the other hand, when the difference is relatively small, the power storage unit 210 and the wiring 106 are electrically connected. This enables rapid hot insertion and removal.

[0223] The predetermined condition may be a condition for realizing rapid hot insertion / removal. Examples of the predetermined condition include (i) a condition indicating that the terminal voltage of the switching unit 230 is within a specific numerical range, (ii) a condition indicating that the terminal voltage of the switching unit 230 is greater than a specific threshold value or is equal to or greater than a specific threshold value, (iii) a condition indicating that the terminal voltage of the switching unit 230 is less than a specific threshold value or is equal to or less than a specific threshold value, and (v) a combination of these conditions.

[0224] (Example of procedure for releasing the over-discharge protection interlock) In a state where the power storage unit 210 of the power storage module 1010 is electrically connected to the wiring 106 of the power storage system 100 and the power storage system 100 is discharging, for example, when the voltage or SOC of the power storage unit 210 becomes smaller than a threshold value for over-discharge protection, the protection unit 250 transmits a signal for activating the over-discharge protection function to the module control unit 1040. At this time, a current flows in the discharging direction between the wiring 106 and the power storage unit 210. In this case, the discharging direction may be an example of the first direction. Also, the charging direction may be an example of the second direction. In this embodiment, the discharging direction and the charging direction are opposite to each other.

[0225] A case where the voltage or SOC of the power storage unit 210 is lower than the threshold for overdischarge protection may be an example of a case where a condition for protecting the power storage unit 210 is not satisfied. In another embodiment, the protection unit 250 may transmit a signal to the module control unit 1040 to activate the overdischarge protection function when the voltage or SOC of the power storage unit 210 is equal to or lower than the threshold for overdischarge protection.

[0226] Upon receiving the above signal, the module control unit 1040 controls the switching unit 230 to electrically disconnect the wiring 106 from the power storage unit 210. If the power storage system 100 continues to discharge even after the wiring 106 and the power storage unit 210 are electrically disconnected, a voltage difference occurs between the wiring 106 and the power storage unit 210.

[0227] When charging of the power storage system 100 is started next time after discharging of the power storage system 100 is completed, a voltage difference occurs between the wiring 106 and the power storage unit 210. In this case, when the absolute value of the voltage difference is greater than the threshold value for realizing rapid hot insertion / removal, the module control unit 1040 determines that the terminal voltage of the switching unit 230 does not satisfy the condition for realizing rapid hot insertion / removal. As a result, charging of the power storage system 100 proceeds in a state in which the power storage unit 210 of the power storage module 1010 and the wiring 106 of the power storage system 100 are electrically disconnected.

[0228] On the other hand, (i) when the absolute value of the voltage difference at the start of charging the power storage system 100 is smaller than or equal to the threshold value for realizing rapid hot plugging / unplugging, or (ii) when the absolute value of the voltage difference becomes smaller than or equal to the threshold value for realizing rapid hot plugging / unplugging as charging of the power storage system 100 progresses, the module control unit 1040 controls the switching unit 230 to electrically connect the wiring 106 and the power storage unit 210. However, at this stage, the voltage or SOC of the power storage unit 210 is smaller than the threshold value for overdischarge protection. Therefore, the interlock mechanism of the module control unit 1040 is activated. As a result, the module control unit 1040 cannot control the switching unit 230 to electrically connect the wiring 106 and the power storage unit 210.

[0229] In order for the module control unit 1040 to control the switching unit 230 to electrically connect the wiring 106 and the power storage unit 210, it is necessary to release the interlock by some logic. The method for releasing the interlock is not particularly limited, but in this embodiment, the module control unit 1040 determines whether or not to release the interlock based on the current flowing between the wiring 106 and the power storage unit 210 or information related to the current, and controls the operation of the switching unit 230.

[0230] 5, the switching unit 230 includes a transistor 520 that adjusts or controls the magnitude of a current flowing in a discharging direction between the wiring 106 and the power storage unit 210. Examples of the transistor 520 include a Si-MOSFET, an insulated gate bipolar transistor (IGBT), a SiC-MOSFET, and a GaN-MOSFET.

[0231] When the rated voltage of the power storage unit 210 is relatively high, the transistor 520 is preferably a SiC-MOSFET. For example, when the maximum value of the rated voltage of the power storage unit 210 is 100V or more, preferably 200V or more, more preferably 300V or more, further preferably 500V or more, further preferably 800V or more, and further preferably 1000V, a SiC-MOSFET is used as the transistor 520. This allows the advantage of the SiC-MOSFET, that is, having excellent withstand voltage characteristics and low loss, to be fully exhibited. When the maximum value of the rated voltage of the power storage unit 210 is 300V or more or 500V or more, the effect of using a SiC-MOSFET as the transistor 520 can be significantly exhibited.

[0232] In addition, a parasitic diode is formed between the source and drain of transistor 520. The parasitic diode passes a current that flows in the charging direction between wiring 106 and power storage unit 210. On the other hand, the parasitic diode prevents a current from flowing in the discharging direction between wiring 106 and power storage unit 210 via the parasitic diode.

[0233] The transistor 520 may be an example of a first current adjustment unit or a second current adjustment unit. The parasitic diode of the transistor 520 may be an example of a first bypass unit or a second bypass unit. Note that the switching unit 230 may include, in addition to the parasitic diode of the transistor 520, a rectifier that has a function similar to that of the parasitic diode and is connected in parallel to the transistor 520 between the wiring 106 and the power storage unit 210. Examples of the rectifier include (i) a rectifier element such as a diode, and (ii) a rectifier circuit composed of a plurality of elements.

[0234] As described above, according to this embodiment, the switching unit 230 includes (i) the transistor 520 that adjusts the current in the discharging direction, and (ii) a parasitic diode that is arranged in parallel with the transistor 520 and passes a current in the charging direction but does not pass a current in the discharging direction. Therefore, when the charging of the power storage system 100 further progresses and the voltage of the wiring 106 becomes higher than the voltage of the positive terminal 212 of the power storage unit 210, a current flows in the charging direction between the wiring 106 and the power storage unit 210 via the parasitic diode of the transistor 520.

[0235] When preventing deterioration or damage of the power storage unit 210 due to over-discharge, the module control unit 1040 needs to prevent a current from flowing in the discharging direction, but does not need to prevent a current from flowing in the charging direction. Therefore, according to this embodiment, the module control unit 1040 monitors the current flowing between the wiring 106 and the power storage unit 210.

[0236] In one embodiment, the module control unit 1040 detects a current flowing in the charging direction between the wiring 106 and the power storage unit 210. In another embodiment, the module control unit 1040 may detect a current flowing between the wiring 106 and the power storage unit 210 when the switching unit 230 electrically disconnects the wiring 106 and the power storage unit 210 in the discharging direction.

[0237] After charging of the power storage system 100 is started, the module control unit 1040 maintains the interlock for over-discharge protection until the above current is detected. On the other hand, when the above current is detected, the module control unit 1040 releases the interlock for over-discharge protection.

[0238] In one embodiment, the module control unit 1040 controls the switching unit 230 to electrically connect the wiring 106 and the power storage unit 210. In general, the on-resistance value of the transistor 520 is smaller than the resistance value of the parasitic diode, so that according to this embodiment, the charging and discharging efficiency of the power storage unit 210 is improved.

[0239] When the above current is detected in a state in which the above voltage difference does not satisfy the condition for realizing rapid hot insertion / removal, the module control unit 1040 may control the switching unit 230 so that the switching unit 230 electrically connects the wiring 106 and the power storage unit 210 at least until the above voltage difference satisfies the condition for realizing rapid hot insertion / removal. Note that while the above voltage difference satisfies the condition for realizing rapid hot insertion / removal, the module control unit 1040 may control the switching unit 230 so that the switching unit 230 electrically connects the wiring 106 and the power storage unit 210.

[0240] In another embodiment, when the above-mentioned current is detected, the module control unit 1040 may transmit a signal for resetting the over-discharge protection function to the protection unit 250. Then, when the protection unit 250 receives the signal for resetting the over-discharge protection function, the protection unit 250 may control the switching unit 230 to electrically connect the wiring 106 and the power storage unit 210.

[0241] When charging of the power storage system 100 further progresses after the wiring 106 and the power storage unit 210 are electrically connected, the voltage or SOC of the power storage unit 210 becomes greater than the threshold for overdischarge protection. When the voltage or SOC of the power storage unit 210 becomes greater than the threshold for overdischarge protection, the protection unit 250 may transmit a signal for resetting the overdischarge protection function to the module control unit 1040. When the module control unit 1040 receives the signal for resetting the overdischarge protection function, it may control the switching unit 230 so that the switching unit 230 electrically connects the power storage unit 210 and the wiring 106.

[0242] As described above, when it is determined to enable the overdischarge protection function, the module control unit 1040, for example, (i) electrically disconnects the wiring 106 and the power storage unit 210, or (ii) reduces the magnitude of the current that can flow in the discharging direction between the wiring 106 and the power storage unit 210. As a result, when the overdischarge protection function is enabled, the magnitude of the current that can flow in the discharging direction is smaller than when the overdischarge protection function is disabled. On the other hand, when it is determined to release the interlock of the overdischarge protection (sometimes referred to as disabling the overdischarge protection function), the module control unit 1040, for example, (i) electrically connects the wiring 106 and the power storage unit 210, or (ii) increases the magnitude of the current that can flow in the discharging direction between the wiring 106 and the power storage unit 210.

[0243] The module control unit 1040 adjusts or controls the magnitude of the current flowing in the discharging direction between the wiring 106 and the power storage unit 210 by adjusting the resistance value or the conduction ratio (sometimes referred to as a duty ratio) of the switching unit 230. In one embodiment, when the switching unit 230 includes a transistor 520 and the transistor 520 is a field effect transistor, the module control unit 1040 can adjust or control the magnitude of the current flowing in the discharging direction between the wiring 106 and the power storage unit 210 by adjusting the gate voltage (sometimes referred to as an input voltage) of the transistor 520. The module control unit 1040 may adjust or control the magnitude of the current flowing in the discharging direction between the wiring 106 and the power storage unit 210 by controlling the operation of an element arranged in a circuit for adjusting the input voltage of the transistor 520.

[0244] In another embodiment, when the switching unit 230 includes a transistor 520 and the transistor 520 is a bipolar transistor, the module control unit 1040 can adjust or control the magnitude of the current flowing in the discharging direction between the wiring 106 and the power storage unit 210 by adjusting the base current (sometimes referred to as the input current) of the transistor 520. The module control unit 1040 may adjust or control the magnitude of the current flowing in the discharging direction between the wiring 106 and the power storage unit 210 by controlling the operation of an element arranged in a circuit for adjusting the input current of the transistor 520.

[0245] The resistance value or the conduction rate of the switching unit 230 may be the same or different between when the over-discharge protection function is enabled and when the over-discharge protection function is disabled. When the switching unit 230 has a switching element, the on-resistance of the switching element may be the same or different between when the over-charge protection function is enabled and when the over-charge protection function is disabled. When the switching unit 230 has a variable resistor, the resistance value of the variable resistor may be the same or different between when the over-charge protection function is enabled and when the over-charge protection function is disabled. When the over-discharge protection function is enabled, the module control unit 1040 may control the switching unit 230 so that the resistance value of the switching unit 230 is larger than when the over-discharge protection function is disabled. When the over-discharge protection function is enabled, the module control unit 1040 may control the switching unit 230 so that the conduction rate of the switching unit 230 is smaller than when the over-discharge protection function is disabled.

[0246] For the purpose of simplifying the explanation, in this embodiment, the procedure for the module control unit 1040 to release the interlock of the over-discharge protection has been described using as an example an embodiment in which (i) when it is determined to enable the over-discharge protection function, the module control unit 1040 electrically disconnects the wiring 106 and the power storage unit 210, and (ii) when it is determined to disable the over-discharge protection function, the module control unit 1040 electrically connects the wiring 106 and the power storage unit 210. However, a person skilled in the art who has come into contact with the description of this specification can understand that the module control unit 1040 can release the interlock of the over-discharge protection by a procedure similar to that of this embodiment even in other embodiments in which (i) when it is determined to enable the over-discharge protection function, the module control unit 1040 reduces the magnitude of the current that can flow in the discharging direction between the wiring 106 and the power storage unit 210, and (ii) when it is determined to disable the over-discharge protection function, the module control unit 1040 increases the magnitude of the current that can flow in the discharging direction between the wiring 106 and the power storage unit 210.

[0247] Specifically, when the over-discharge protection function is enabled, in this embodiment, the series of operations performed by the module control unit 1040 to electrically disconnect the wiring 106 and the power storage unit 210 corresponds to the series of operations performed by the module control unit 1040 to reduce the current that can flow between the power storage unit 210 and the wiring 106 in the other embodiments described above. Similarly, when the over-discharge protection function is disabled, in this embodiment, the series of operations performed by the module control unit 1040 to electrically connect the wiring 106 and the power storage unit 210 corresponds to the series of operations performed by the module control unit 1040 to increase the current that can flow between the power storage unit 210 and the wiring 106 in the other embodiments described above.

[0248] (Example of procedure for disabling the overcharge protection interlock) In a state where the power storage unit 210 of the power storage module 1010 is electrically connected to the wiring 106 of the power storage system 100 and the power storage system 100 is charging, for example, when the voltage or SOC of the power storage unit 210 becomes greater than a threshold value for overcharge protection, the protection unit 250 transmits a signal for activating the overcharge protection function to the module control unit 1040. At this time, a current flows in the charging direction between the wiring 106 and the power storage unit 210. In this case, the charging direction may be an example of the first direction. Also, the discharging direction may be an example of the second direction. In this embodiment, the discharging direction and the charging direction are opposite to each other.

[0249] A case where the voltage or SOC of the power storage unit 210 is greater than the threshold for overcharge protection may be an example of a case where the condition for protecting the power storage unit 210 is not satisfied. In another embodiment, the protection unit 250 may transmit a signal to the module control unit 1040 to activate the overcharge protection function when the voltage or SOC of the power storage unit 210 is equal to or greater than the threshold for overdischarge protection.

[0250] Upon receiving the above signal, the module control unit 1040 controls the switching unit 230 to electrically disconnect the wiring 106 from the power storage unit 210. If the power storage system 100 continues charging even after the wiring 106 and the power storage unit 210 are electrically disconnected, a voltage difference occurs between the wiring 106 and the power storage unit 210.

[0251] When the charging of the power storage system 100 is completed and the discharging of the power storage system 100 is started next time, a voltage difference occurs between the wiring 106 and the power storage unit 210. In this case, when the absolute value of the voltage difference is larger than the threshold value for realizing rapid hot insertion / removal, the module control unit 1040 determines that the terminal voltage of the switching unit 230 does not satisfy the condition for realizing rapid hot insertion / removal. As a result, the discharging of the power storage system 100 progresses in a state in which the power storage unit 210 of the power storage module 1010 and the wiring 106 of the power storage system 100 are electrically disconnected.

[0252] On the other hand, (i) when the absolute value of the voltage difference at the start of discharge of the power storage system 100 is smaller than or equal to the threshold value for realizing rapid hot plugging / unplugging, or (ii) when the charging of the power storage system 100 progresses and the absolute value of the voltage difference becomes smaller than or equal to the threshold value for realizing rapid hot plugging / unplugging, the module control unit 1040 controls the switching unit 230 to electrically connect the wiring 106 and the power storage unit 210. However, at this stage, the voltage or SOC of the power storage unit 210 is larger than the threshold value for overcharge protection. Therefore, the interlock mechanism of the module control unit 1040 is activated. As a result, the module control unit 1040 cannot control the switching unit 230 to electrically connect the wiring 106 and the power storage unit 210.

[0253] In order for the module control unit 1040 to control the switching unit 230 to electrically connect the wiring 106 and the power storage unit 210, it is necessary to release the interlock by some logic. The method for releasing the interlock is not particularly limited, but in this embodiment, the module control unit 1040 determines whether or not to release the interlock based on the current flowing between the wiring 106 and the power storage unit 210 or information related to the current, and controls the operation of the switching unit 230.

[0254] 5, the switching unit 230 includes a transistor 510 that adjusts or controls the magnitude of a current flowing in the charging direction between the wiring 106 and the power storage unit 210. Examples of the transistor 510 include a Si-MOSFET, an insulated gate bipolar transistor (IGBT), a SiC-MOSFET, and a GaN-MOSFET.

[0255] When the rated voltage of the power storage unit 210 is relatively high, the transistor 510 is preferably a SiC-MOSFET. For example, when the maximum value of the rated voltage of the power storage unit 210 is 100V or more, preferably 200V or more, more preferably 300V or more, further preferably 500V or more, further preferably 800V or more, and further preferably 1000V, a SiC-MOSFET is used as the transistor 510. This makes it possible to fully utilize the advantages of the SiC-MOSFET, that is, the excellent withstand voltage characteristics and the small loss. When the maximum value of the rated voltage of the power storage unit 210 is 300V or more or 500V or more, the effect of using a SiC-MOSFET as the transistor 510 can be significantly achieved.

[0256] In addition, a parasitic diode is formed between the source and drain of transistor 510. The parasitic diode passes a current flowing in the discharging direction between wiring 106 and power storage unit 210. On the other hand, the parasitic diode prevents a current from flowing in the charging direction between wiring 106 and power storage unit 210 via the parasitic diode.

[0257] The transistor 510 may be an example of a first current adjustment unit or a second current adjustment unit. The parasitic diode of the transistor 510 may be an example of a first bypass unit or a second bypass unit. Note that the switching unit 230 may include, in addition to the parasitic diode of the transistor 510, a rectifier that has a function similar to that of the parasitic diode and is connected in parallel to the transistor 510 between the wiring 106 and the power storage unit 210. Examples of the rectifier include (i) a rectifier element such as a diode, and (ii) a rectifier circuit composed of a plurality of elements.

[0258] As described above, according to this embodiment, the switching unit 230 includes (i) the transistor 510 that adjusts the current in the charging direction, and (ii) a parasitic diode that is arranged in parallel with the transistor 510 and passes a current in the discharging direction but does not pass a current in the charging direction. Therefore, when the discharge of the power storage system 100 further progresses and the voltage of the wiring 106 becomes smaller than the voltage of the positive terminal 212 of the power storage unit 210, a current flows in the discharging direction between the wiring 106 and the power storage unit 210 via the parasitic diode of the transistor 510.

[0259] When preventing deterioration or damage of the power storage unit 210 due to overcharging, the module control unit 1040 needs to prevent a current from flowing in the charging direction, but does not need to prevent a current from flowing in the discharging direction. Therefore, according to this embodiment, the module control unit 1040 monitors the current flowing between the wiring 106 and the power storage unit 210.

[0260] In one embodiment, the module control unit 1040 detects a current flowing in the discharging direction between the wiring 106 and the power storage unit 210. In another embodiment, the module control unit 1040 may detect a current flowing between the wiring 106 and the power storage unit 210 when the switching unit 230 electrically disconnects the wiring 106 and the power storage unit 210 in the charging direction.

[0261] After the discharge of the power storage system 100 is started, the module control unit 1040 maintains the interlock for overcharge protection until the above current is detected. On the other hand, when the above current is detected, the module control unit 1040 releases the interlock for overcharge protection.

[0262] In one embodiment, the module control unit 1040 controls the switching unit 230 to electrically connect the wiring 106 and the power storage unit 210. In general, the on-resistance value of the transistor 510 is smaller than the resistance value of the parasitic diode, so that according to this embodiment, the charging and discharging efficiency of the power storage unit 210 is improved.

[0263] When the above current is detected in a state in which the above voltage difference does not satisfy the condition for realizing rapid hot insertion / removal, the module control unit 1040 may control the switching unit 230 so that the switching unit 230 electrically connects the wiring 106 and the power storage unit 210 at least until the above voltage difference satisfies the condition for realizing rapid hot insertion / removal. Note that while the above voltage difference satisfies the condition for realizing rapid hot insertion / removal, the module control unit 1040 may control the switching unit 230 so that the switching unit 230 electrically connects the wiring 106 and the power storage unit 210.

[0264] In another embodiment, when the above current is detected, the module control unit 1040 may transmit a signal for resetting the overcharge protection function to the protection unit 250. Then, when the protection unit 250 receives the signal for resetting the overcharge protection function, the protection unit 250 may control the switching unit 230 to electrically connect the wiring 106 and the power storage unit 210.

[0265] When the discharge of the power storage system 100 further progresses after the wiring 106 and the power storage unit 210 are electrically connected, the voltage or SOC of the power storage unit 210 becomes smaller than the threshold for overcharge protection. When the voltage or SOC of the power storage unit 210 becomes smaller than the threshold for overcharge protection, the protection unit 250 may transmit a signal for resetting the overcharge protection function to the module control unit 1040. When the module control unit 1040 receives the signal for resetting the overcharge protection function, the module control unit 1040 may control the switching unit 230 so that the switching unit 230 electrically connects the power storage unit 210 and the wiring 106.

[0266] As described above, when it is determined to enable the overcharge protection function, the module control unit 1040, for example, (i) electrically disconnects the wiring 106 and the power storage unit 210, or (ii) reduces the magnitude of a current that can flow in the charging direction between the wiring 106 and the power storage unit 210. As a result, when the overcharge protection function is enabled, the magnitude of a current that can flow in the charging direction is smaller than when the overcharge protection function is disabled. On the other hand, when it is determined to release the interlock of the overcharge protection (sometimes referred to as disabling the overcharge protection function), the module control unit 1040, for example, (i) electrically connects the wiring 106 and the power storage unit 210, or (ii) increases the magnitude of a current that can flow in the charging direction between the wiring 106 and the power storage unit 210.

[0267] The module control unit 1040 adjusts or controls the magnitude of the current flowing in the charging direction between the wiring 106 and the power storage unit 210 by adjusting the resistance value or the conduction ratio (sometimes referred to as a duty ratio) of the switching unit 230. In one embodiment, when the switching unit 230 includes a transistor 510 and the transistor 510 is a field effect transistor, the module control unit 1040 can adjust or control the magnitude of the current flowing in the charging direction between the wiring 106 and the power storage unit 210 by adjusting the gate voltage (sometimes referred to as an input voltage) of the transistor 510. The module control unit 1040 may adjust or control the magnitude of the current flowing in the charging direction between the wiring 106 and the power storage unit 210 by controlling the operation of an element arranged in a circuit for adjusting the input voltage of the transistor 510.

[0268] In another embodiment, when the switching unit 230 includes a transistor 510 and the transistor 510 is a bipolar transistor, the module control unit 1040 can adjust or control the magnitude of the current flowing in the charging direction between the wiring 106 and the power storage unit 210 by adjusting the base current (sometimes referred to as the input current) of the transistor 510. The module control unit 1040 may adjust or control the magnitude of the current flowing in the charging direction between the wiring 106 and the power storage unit 210 by controlling the operation of an element arranged in a circuit for adjusting the input current of the transistor 510.

[0269] The resistance value or the conduction rate of the switching unit 230 may be the same or different between when the overcharge protection function is enabled and when the overcharge protection function is disabled. When the switching unit 230 has a switching element, the on-resistance of the switching element may be the same or different between when the overcharge protection function is enabled and when the overcharge protection function is disabled. When the switching unit 230 has a variable resistor, the resistance value of the variable resistor may be the same or different between when the overcharge protection function is enabled and when the overcharge protection function is disabled. When the overcharge protection function is enabled, the module control unit 1040 may control the switching unit 230 so that the resistance value of the switching unit 230 is larger than when the overcharge protection function is disabled. When the overcharge protection function is enabled, the module control unit 1040 may control the switching unit 230 so that the conduction rate of the switching unit 230 is smaller than when the overcharge protection function is disabled.

[0270] For the purpose of simplifying the explanation, in this embodiment, the procedure for the module control unit 1040 to release the interlock of the overcharge protection has been described using as an example an embodiment in which (i) when it is determined to enable the overcharge protection function, the module control unit 1040 electrically disconnects the wiring 106 and the power storage unit 210, and (ii) when it is determined to disable the overcharge protection function, the module control unit 1040 electrically connects the wiring 106 and the power storage unit 210. However, a person skilled in the art who has read the description of this specification can understand that the module control unit 1040 can release the interlock of the overcharge protection by a procedure similar to that of this embodiment even in other embodiments in which (i) when it is determined to enable the overcharge protection function, the module control unit 1040 reduces the magnitude of the current that can flow in the charging direction between the wiring 106 and the power storage unit 210, and (ii) when it is determined to disable the overcharge protection function, the module control unit 1040 increases the magnitude of the current that can flow in the charging direction between the wiring 106 and the power storage unit 210.

[0271] Specifically, when the overcharge protection function is enabled, in this embodiment, a series of operations by the module control unit 1040 to electrically disconnect the wiring 106 and the power storage unit 210 corresponds to a series of operations by the module control unit 1040 to reduce the current that can flow between the power storage unit 210 and the wiring 106 in the other embodiments described above. Similarly, when the overcharge protection function is disabled, in this embodiment, a series of operations by the module control unit 1040 to electrically connect the wiring 106 and the power storage unit 210 corresponds to a series of operations by the module control unit 1040 to increase the current that can flow between the power storage unit 210 and the wiring 106 in the other embodiments described above.

[0272] As described above, according to this embodiment, the module control unit 1040 can achieve both the hot insertion / removal function and the protection function of the power storage unit 210 without significantly reducing the charge / discharge efficiency of the power storage module 1010, for example.

[0273] In the present embodiment, the current detection element 1020 and the switching unit 230 are disposed between the positive terminal 202 of the power storage module 1010 and the positive terminal 212 of the power storage unit 210, and the positive terminal 212 of the power storage unit 210 is electrically connected to the wiring 106 via the switching unit 230. However, the arrangement of the current detection element 1020 and the switching unit 230 is not limited to this embodiment. In another embodiment, the current detection element 1020 and the switching unit 230 are disposed between the negative terminal 204 of the power storage module 1010 and the negative terminal 214 of the power storage unit 210, and the negative terminal 214 of the power storage unit 210 is electrically connected to the wiring 106 via the switching unit 230.

[0274] The power storage module 1010 may be an example of a second power storage device. The switching unit 230 of the power storage module 1010 may be an example of a second switching unit.

[0275] 11 shows an example of a system configuration of the module control unit 1040. In this embodiment, the module control unit 1040 includes a determination unit 410, a receiving unit 420, and a signal generation unit 430. The module control unit 1040 may include a module information acquisition unit 440, a module information storage unit 450, and a module information transmission unit 460. In this embodiment, the module control unit 1040 includes a current monitoring unit 1120. In this embodiment, the current monitoring unit 1120 includes a current detection unit 1122 and a direction determination unit 1124. The signal generation unit 430 may be an example of an operation control unit.

[0276] In this embodiment, the module control unit 1040 differs from the module control unit 240 in that it includes a current monitoring unit 1120. Regarding configurations other than the above differences, the module control unit 1040 may have similar features to the corresponding configurations of the module control unit 240.

[0277] In this embodiment, the current monitoring unit 1120 monitors the current flowing between the wiring 106 of the power storage system 100 and the power storage unit 210 of the power storage module 1010. For example, the current monitoring unit 1120 monitors the current flowing between the positive terminal 202 and the positive terminal 212 of the power storage module 1010.

[0278] In this embodiment, the current detection unit 1122 detects a current flowing between the wiring 106 of the power storage system 100 and the power storage unit 210 of the power storage module 1010. The current detection unit 1122 may determine the magnitude of the current. The current detection unit 1122 may be configured with any analog circuit or any digital circuit.

[0279] In this embodiment, the direction determination unit 1124 determines the direction of a current flowing between the wiring 106 of the power storage system 100 and the power storage unit 210 of the power storage module 1010. The direction determination unit 1124 may be configured with any analog circuit or any digital circuit.

[0280] Fig. 12 shows an example of a circuit configuration of the module control unit 1040. Fig. 12 shows an example of a circuit configuration of the switching unit 230. Fig. 12 shows an example of the switching unit 230 and an example of the module control unit 1040 together with the positive terminal 202, the negative terminal 204, the power storage unit 210, the protection unit 250, and the current detection element 1020.

[0281] [Specific example of the circuit of the switching unit 230] In this embodiment, one end of the transistor 510 is electrically connected to the wiring 106, and the other end is electrically connected to the power storage unit 210. The transistor 510 is connected in series to the transistor 520 and the parasitic diode 1244 between the wiring 106 and the power storage unit 210. In this embodiment, the transistor 510 adjusts the magnitude of the current flowing between the wiring 106 and the power storage unit 210 in the charging direction.

[0282] In this embodiment, one end of the transistor 520 is electrically connected to the wiring 106, and the other end is electrically connected to the power storage unit 210. The transistor 520 is connected in series with the transistor 510 and the parasitic diode 1242 between the wiring 106 and the power storage unit 210. In this embodiment, the transistor 520 adjusts the magnitude of the current flowing between the wiring 106 and the power storage unit 210 in the discharge direction.

[0283] The parasitic diode 1242 has one end electrically connected to the wiring 106 and the other end electrically connected to the power storage unit 210. The parasitic diode 1242 is connected in parallel to the transistor 510 between the wiring 106 and the power storage unit 210. The parasitic diode 1242 is connected in series to the transistor 520 and the parasitic diode 1244 between the wiring 106 and the power storage unit 210.

[0284] Parasitic diode 1242 passes a current flowing in the discharging direction between wiring 106 and power storage unit 210. On the other hand, parasitic diode 1242 prevents a current from flowing in the charging direction between wiring 106 and power storage unit 210 via parasitic diode 1242.

[0285] The parasitic diode 1244 has one end electrically connected to the wiring 106 and the other end electrically connected to the power storage unit 210. The parasitic diode 1244 is connected in parallel to the transistor 520 between the wiring 106 and the power storage unit 210. The parasitic diode 1244 is connected in series to the transistor 510 and the parasitic diode 1242 between the wiring 106 and the power storage unit 210.

[0286] Parasitic diode 1242 passes a current flowing in the charging direction between wiring 106 and power storage unit 210. On the other hand, parasitic diode 1244 prevents a current from flowing in the discharging direction between wiring 106 and power storage unit 210 via parasitic diode 1244.

[0287] The transistor 510 may be an example of one of the first current adjustment section and the second current adjustment section. The transistor 520 may be an example of the other of the first current adjustment section and the second current adjustment section. The parasitic diode 1242 may be an example of one of the first bypass section and the second bypass section. The parasitic diode 1244 may be an example of the other of the first bypass section and the second bypass section. The discharging direction may be an example of one of the first direction and the second direction. The charging direction may be an example of the other of the first direction and the second direction.

[0288] [Specific example of the circuit of the module control unit 1040] In this embodiment, the module control unit 1040 includes a determination unit 410, a signal generation unit 430, and a current monitoring unit 1120. The determination unit 410 may be an example of a first determination unit, a second determination unit, and a third determination unit.

[0289] In this embodiment, the signal generating unit 430 includes an OR circuit 1260, an AND circuit 1272, an AND circuit 1274, an OR circuit 1282, and an OR circuit 1284. In this embodiment, a resistor having an appropriate resistance value is disposed as the current detecting element 1020 between the positive terminal 202 and the switching unit 230. The resistance value of the current detecting element 1020 is determined, for example, so that the current monitoring unit 1120 can reliably determine the direction of the current flowing between the wiring 106 and the power storage unit 210.

[0290] In this embodiment, the determination unit 410 determines whether or not the voltage between the terminals of the switching unit 230 is within a predetermined range. The determination unit 410 transmits a signal indicating the determination result to the signal generating unit 430. The determination unit 410 may be configured with any analog circuit, or may be configured with any digital circuit. The determination unit 410 may include a window comparator. The window comparator can be realized, for example, by using two comparators.

[0291] In this embodiment, the determination unit 410 has two input terminals. A voltage at one end of the switching unit 230 (for example, an end on the positive terminal 202 side) is input to one input terminal of the determination unit 410 (shown as a - terminal in the figure). A voltage at the other end of the switching unit 230 (for example, an end on the power storage unit 210 side) is input to the other input terminal of the determination unit 410 (shown as a + terminal in the figure).

[0292] In this embodiment, the determination unit 410 has two output terminals. The determination unit 410 outputs a signal indicating that the terminal voltage of the switching unit 230 is smaller than a first threshold from one output terminal (shown as an L terminal in the figure) as a signal indicating the determination result. For example, when the terminal voltage of the switching unit 230 is smaller than the first threshold, the determination unit 410 outputs H logic from the L terminal. On the other hand, when the terminal voltage of the switching unit 230 is equal to or greater than the first threshold, the determination unit 410 outputs L logic from the L terminal.

[0293] Furthermore, the determination unit 410 outputs a signal indicating that the terminal voltage of the switching unit 230 is greater than the second threshold from the other output terminal (shown as an H terminal in the figure) as a signal indicating the determination result. In this embodiment, a value greater than the absolute value of the first threshold is set as the absolute value of the second threshold. For example, when the terminal voltage of the switching unit 230 is greater than the second threshold, the determination unit 410 outputs H logic from the H terminal. On the other hand, when the terminal voltage of the switching unit 230 is equal to or less than the second threshold, the determination unit 410 outputs L logic from the H terminal.

[0294] In one embodiment, the determination unit 410 can determine, for example, whether or not the voltage or SOC of the power storage unit 210 meets a first condition. Examples of the first condition include (i) a condition indicating that the voltage or SOC of the power storage unit is outside a predetermined first numerical range, (ii) a condition indicating that the voltage or SOC of the power storage unit is greater than a predetermined first threshold, and (iii) a condition indicating that the voltage or SOC of the power storage unit is equal to or greater than a first threshold. The first condition is, for example, a condition indicating that the power storage unit 210 is overcharged.

[0295] In another embodiment, the determination unit 410 can determine, for example, whether or not the voltage or SOC of the power storage unit 210 meets a second condition. Examples of the second condition include (i) a condition indicating that the voltage or SOC of the power storage unit is outside a predetermined second numerical range, (ii) a condition indicating that the voltage or SOC of the power storage unit is smaller than a predetermined second threshold, and (iii) a condition indicating that the voltage or SOC of the power storage unit is equal to or lower than the second threshold. Note that the second condition may be a condition different from the first condition. The second condition is, for example, a condition indicating that the power storage unit 210 is over-discharged.

[0296] In still another embodiment, the determination unit 410 can determine, for example, whether or not the terminal voltage of the switching unit 230 satisfies a third condition. Examples of the third condition include (i) a condition indicating that the terminal voltage of the switching unit 230 is within a predetermined third numerical range, (ii) a condition indicating that the terminal voltage of the switching unit 230 is smaller than a predetermined third threshold value, and (iii) a condition indicating that the terminal voltage of the switching unit 230 is equal to or smaller than the third threshold value.

[0297] In still another embodiment, the determination unit 410 can determine, for example, whether or not the terminal voltage of the switching unit 230 meets a fourth condition. Examples of the fourth condition include (i) a condition indicating that the terminal voltage of the switching unit 230 is outside a predetermined fourth numerical range, (ii) a condition indicating that the terminal voltage of the switching unit 230 is greater than a predetermined fourth threshold, and (iii) a condition indicating that the terminal voltage of the switching unit 230 is equal to or greater than the fourth threshold. The fourth numerical range may be the same as the third numerical range. The upper limit of the fourth numerical range may be greater than the upper limit of the third numerical range. The fourth threshold may be the same as the third threshold. The fourth threshold may be greater than the third threshold.

[0298] In this embodiment, the current monitoring unit 1120 may include a comparator. The current monitoring unit 1120 has, for example, two input terminals and one output terminal. A voltage at one end of the current detection element 1020 (for example, an end on the positive terminal 202 side) is input to one input terminal of the current monitoring unit 1120 (shown as a + terminal in the figure). A voltage at the other end of the current detection element 1020 (for example, an end on the switching unit 230 side) is input to the other input terminal of the current monitoring unit 1120 (shown as a - terminal in the figure).

[0299] For example, if the voltage input to the + terminal is greater than the voltage input to the - terminal, the current monitoring unit 1120 outputs a logical H from the output terminal. On the other hand, if the voltage input to the + terminal is less than the voltage input to the - terminal, the current monitoring unit 1120 outputs a logical L from the output terminal. Furthermore, if the voltage input to the + terminal and the voltage input to the - terminal are equal, or can be considered to be equal, the current monitoring unit 1120 does not output a signal from the output terminal.

[0300] In this embodiment, the current monitoring unit 1120 detects a current flowing between the wiring 106 and the power storage unit 210 when at least one of the transistor 510 and the transistor 520 electrically disconnects the wiring 106 and the power storage unit 210. In one embodiment, the current monitoring unit 1120 detects a current flowing in the discharging direction between the wiring 106 and the power storage unit 210 when the overcharge protection function is enabled. In another embodiment, the current monitoring unit 1120 detects a current flowing in the charging direction between the wiring 106 and the power storage unit 210 when the overdischarge protection function is enabled.

[0301] In this embodiment, the signal generating unit 430 may also have the function of the receiving unit 420. For example, the signal generating unit 430 receives a signal 86 for activating the overdischarge protection function from the protection unit 250. The signal generating unit 430 also receives a signal 88 for activating the overcharge protection function from the protection unit 250. The signal generating unit 430 receives information on the inter-terminal voltage of the switching unit 230 from the determination unit 410. The signal generating unit 430 receives information on the current between the wiring 106 and the power storage unit 210 from the current monitoring unit 1120.

[0302] In this embodiment, the signal generating unit 430 can control the operation of at least one of the transistors 510 and 520 based on (i) the voltage or SOC of the power storage unit 210, and (ii) the detection result of the current monitoring unit 1120. The signal generating unit 430 can control the operation of at least one of the transistors 510 and 520 based on (i) the voltage or SOC of the power storage unit 210, and (ii) the detection result of the current monitoring unit 1120, and (iii) the determination result of the determination unit 410. The signal generating unit 430 may control at least one of the transistors 510 and 520 by outputting a signal for controlling the operation of at least one of the transistors 510 and 520 to the transistor that is to be controlled by the signal.

[0303] In this embodiment, when the determination unit 410 determines that the terminal voltage of the switching unit 230 satisfies the fourth condition, the signal generation unit 430 may output a signal to at least one of the transistor 510 and the transistor 520 to perform an operation of electrically disconnecting the wiring 106 and the power storage unit 210, or an operation of reducing the current flowing between the wiring 106 and the power storage unit 210. In this way, the determination unit 410 can also be used as an overcurrent protection function for the power storage unit 210.

[0304] In this embodiment, the OR circuit 1260 has two input terminals and one output terminal. An output from an H terminal of the determination unit 410 is input to one input terminal of the OR circuit 1260. An output from an L terminal of the determination unit 410 is input to the other input terminal of the OR circuit 1260.

[0305] The OR circuit 1260 outputs the logical sum of the two inputs. For example, when the terminal voltage of the switching unit 230 falls within a specific numerical range, the OR circuit 1260 outputs L logic. On the other hand, when the terminal voltage of the switching unit 230 falls outside the specific numerical range, the OR circuit 1260 outputs H logic. For example, as an example of a case where the switching unit 230 meets the above fourth condition, when the terminal voltage of the switching unit 230 is greater than a specific value, H logic is output from the H terminal of the determination unit 410. In this case, the OR circuit 1260 outputs H logic.

[0306] In this embodiment, the AND circuit 1272 has two input terminals and one output terminal. A signal obtained by inverting the output of the OR circuit 1260 is input to one input terminal of the AND circuit 1272. A signal obtained by inverting the signal 88 for enabling the overcharge protection function is input to the other input terminal of the AND circuit 1272.

[0307] The AND circuit 1272 outputs the logical product of the two inputs. For example, when the terminal voltage of the switching unit 230 falls within a specific numerical range (specifically, when the absolute value of the difference between the voltage of the wiring 106 and the voltage of the power storage unit 210 is smaller than a specific threshold value or is equal to or less than the threshold value), and when the voltage or SOC of the power storage unit 210 is smaller than the threshold value for overcharge protection, the AND circuit 1272 outputs H logic. On the other hand, in other cases, the AND circuit 1272 outputs L logic.

[0308] In this embodiment, the AND circuit 1274 has two input terminals and one output terminal. A signal obtained by inverting the output of the OR circuit 1260 is input to one input terminal of the AND circuit 1274. A signal obtained by inverting the signal 86 for enabling the over-discharge protection function is input to the other input terminal of the AND circuit 1274.

[0309] The AND circuit 1274 outputs the logical product of the two inputs. For example, when the terminal voltage of the switching unit 230 falls within a specific numerical range (specifically, when the absolute value of the difference between the voltage of the wiring 106 and the voltage of the power storage unit 210 is smaller than a specific threshold value or equal to or less than the threshold value), and when the voltage or SOC of the power storage unit 210 is larger than the threshold value for overdischarge protection, the AND circuit 1274 outputs H logic. On the other hand, in other cases, the AND circuit 1274 outputs L logic.

[0310] In this embodiment, the OR circuit 1282 has two input terminals and one output terminal. A signal obtained by inverting the output of the current monitoring unit 1120 is input to one input terminal of the OR circuit 1282. The output of the AND circuit 1272 is input to the other input terminal of the OR circuit 1282.

[0311] The OR circuit 1282 outputs a logical sum of two inputs. For example, when the output of the OR circuit 1282 is logic H, the transistor 510 operates on, and when the output of the OR circuit 1282 is logic L, the transistor 510 operates off. In one embodiment, when a current flows in the discharging direction between the wiring 106 and the power storage unit 210, the OR circuit 1282 outputs logic H. In another embodiment, when the voltage between the terminals of the switching unit 230 falls within a specific numerical range and the voltage or SOC of the power storage unit 210 is smaller than a threshold for overcharge protection, the OR circuit 1282 outputs logic H.

[0312] In this embodiment, the OR circuit 1284 has two input terminals and one output terminal. The output of the current monitoring unit 1120 is input to one input terminal of the OR circuit 1284. The output of the AND circuit 1274 is input to the other input terminal of the OR circuit 1284.

[0313] The OR circuit 1284 outputs the logical sum of the two inputs. For example, when the output of the OR circuit 1284 is H logic, the transistor 520 operates on, and when the output of the OR circuit 1284 is L logic, the transistor 520 operates off. In one embodiment, when a current flows between the wiring 106 and the power storage unit 210 in the charging direction, the OR circuit 1284 outputs H logic. In another embodiment, when the voltage between the terminals of the switching unit 230 falls within a specific numerical range and the voltage or SOC of the power storage unit 210 is smaller than a threshold for overcharge protection, the OR circuit 1284 outputs H logic.

[0314] [Specific example of operation of signal generating unit 430] In one embodiment, when the determination unit 410 determines that the voltage or SOC of the power storage unit 210 satisfies the first condition, the signal generation unit 430 outputs, for example, a signal to the transistor 510 to perform an operation of electrically disconnecting the wiring 106 and the power storage unit 210, or an operation of reducing the current flowing in the charging direction between the wiring 106 and the power storage unit 210. Depending on the content of the first condition, the signal generation unit 430 may output a signal to the transistor 520.

[0315] In another embodiment, when the determination unit 410 determines that the voltage or SOC of the power storage unit 210 satisfies the second condition, the signal generation unit 430 outputs, for example, a signal to the transistor 520 to perform an operation of electrically disconnecting the wiring 106 and the power storage unit 210, or an operation of reducing the current flowing in the discharging direction between the wiring 106 and the power storage unit 210. Depending on the content of the second condition, the signal generation unit 430 may output a signal to the transistor 510.

[0316] In still another embodiment, when the determination unit 410 determines that the terminal voltage of the switching unit 230 meets the third condition, the signal generation unit 430 outputs a signal to the transistor 510 and the transistor 520 to perform an operation of electrically connecting the wiring 106 and the power storage unit 210, or an operation of increasing the current flowing between the wiring 106 and the power storage unit 210, regardless of whether the voltage or SOC of the power storage unit 210 meets the first condition and the second condition. On the other hand, when the determination unit 410 determines that the terminal voltage of the switching unit 230 does not meet the third condition, the signal generation unit 430 may output a signal according to the detection result of the current monitoring unit 1120. For example, the signal generation unit 430 outputs a signal as follows.

[0317] [(a) when the determination unit 410 determines that the terminal voltage of the switching unit 230 does not satisfy the third condition, (b) when the current monitoring unit 1120 detects (i) a current flowing in the discharging direction between the wiring 106 and the power storage unit 210 when the overcharge protection function is enabled, or (ii) a current flowing between the wiring 106 and the power storage unit 210 when the transistor 510 electrically disconnects the wiring 106 and the power storage unit] In this case, regardless of whether the voltage or SOC of the power storage unit 210 satisfies the first condition, the signal generating unit 430 outputs a signal to the transistor 510 to perform an operation of electrically connecting the wiring 106 and the power storage unit 210, or an operation of increasing the current flowing between the wiring 106 and the power storage unit 210.

[0318] [(a) when the determination unit 410 determines that the terminal voltage of the switching unit 230 does not satisfy the third condition, (c) when the current monitoring unit 1120 detects (i) a current flowing in the charging direction between the wiring 106 and the power storage unit 210 when the over-discharge protection function is enabled, or (ii) a current flowing between the wiring 106 and the power storage unit 210 when the transistor 520 electrically disconnects the wiring 106 and the power storage unit] In this case, regardless of whether the voltage or SOC of the power storage unit 210 satisfies the second condition, the signal generating unit 430 outputs a signal to the transistor 520 to perform an operation of electrically connecting the wiring 106 and the power storage unit 210, or an operation of increasing the current flowing between the wiring 106 and the power storage unit 210.

[0319] In still another embodiment, the module control unit 1040 can suppress deterioration or damage caused by an overcurrent in the power storage unit 210. As described above, as an example of a case where the switching unit 230 satisfies the fourth condition, when the inter-terminal voltage of the switching unit 230 is greater than a specific value, the OR circuit 1260 outputs an H logic.

[0320] Therefore, when a current flows between the wiring 106 and the power storage unit 210 in the discharging direction and the voltage between the terminals of the switching unit 230 is greater than a specific value, the OR circuit 1282 outputs L logic. As a result, the transistor 510 turns off. Similarly, when a current flows between the wiring 106 and the power storage unit 210 in the charging direction and the voltage between the terminals of the switching unit 230 is greater than a specific value, the OR circuit 1284 outputs L logic. As a result, the transistor 520 turns off.

[0321] According to the present embodiment, a steady current flow through the parasitic diodes 1242 and 1244 is suppressed. As a result, it can be considered that the voltage between the terminals of the switching unit 230 is proportional to the current flowing through the transistors 510 and 520. Thus, by appropriately setting the resistance value of the current detection element 1020 or by connecting a resistor having an appropriate resistance value in series with the current detection element 1020 between the wiring 106 and the power storage unit 210, the determination unit 410 and the signal generation unit 430 can be used as an overcurrent protection circuit.

[0322] Next, other examples of the power storage module 130 will be described with reference to Figs. 13 and 14. To the extent that there is no technical contradiction, the matters described for the power storage module 130 and each part thereof may be applied to other examples of the power storage module 130 and each part thereof. Furthermore, the matters described for the other examples of the power storage module 130 and each part thereof may be applied to the power storage module 130 and each part thereof. In the description of Figs. 13 to 14, the matters described for each part of the power storage module 130 may be omitted.

[0323] 13, the power storage module 1330 differs from the power storage module 1010 in that the power storage module 1330 includes a trickle charge unit 320. Other than the above differences, the power storage module 1330 may have the same configuration as the power storage module 1010.

[0324] 14, the power storage module 1430 differs from the power storage module 1330 in that when the module control unit 1040 decides to release at least one of the overdischarge protection interlock and the overcharge protection interlock, the module control unit 1040 transmits at least one of a reset signal for overdischarge protection and a reset signal for overcharge protection to the protection unit 250. The power storage module 1430 also differs from the power storage module 1330 in that when the protection unit 250 receives a reset signal, the protection unit 250 controls the switching unit 230 to release at least one of the overdischarge protection interlock and the overcharge protection interlock. Regarding configurations other than the above differences, the power storage module 1430 may have similar features to the corresponding configurations of the power storage module 1330.

[0325] The power storage module 1330 may be an example of a first power storage device. The power storage module 1430 may be an example of a first power storage device.

[0326] In each of the above embodiments, the details of the power storage system 100 have been described by taking the case where the switching unit is arranged inside the power storage module as an example. However, the power storage system 100 is not limited to each of the above embodiments. In other embodiments, the switching unit may be arranged outside the power storage module. For example, the switching unit is arranged between the connection terminal 102 of the power storage system 100 and the positive terminal 202 of each power storage module. The switching unit may be arranged between the connection terminal 104 of the power storage system 100 and the negative terminal 204 of each power storage module. The above switching unit arranged inside or outside each power storage module may be referred to as the switching unit of each power storage module regardless of the installation location of the switching unit.

[0327] [Other examples of power supply systems] Another example of the power supply system 10 will be described with reference to Fig. 15 and Fig. 16. Fig. 15 shows an example of the system configuration of the power supply system 10. Fig. 16 shows an example of the system configuration of a power storage module 1630.

[0328] The power supply system 10 according to Fig. 15 differs from the power supply system 10 described in relation to Fig. 1 in that the power supply system 10 according to Fig. 15 includes a power storage system 1500 instead of the power storage system 100. Regarding characteristics other than the above differences, the power supply system 10 according to Fig. 15 may have a similar configuration to the power supply system 10 described in relation to Fig. 1.

[0329] To the extent that there is no technical contradiction, the matters described for the power storage system 100 and each part thereof may be applied to the power storage system 1500 and each part thereof. Furthermore, the matters described for the power storage system 1500 and each part thereof may be applied to the power storage system 100 and each part thereof. In the description of Figs. 15 and 16, the matters described for each part of the power storage system 100 may be omitted.

[0330] As shown in FIG. 15, the power storage system 1500 differs from the power storage system 100 in that a power storage module group 1510 is provided instead of the power storage module 110, and in that a power storage module group 1530 is provided instead of the power storage module .

[0331] In this embodiment, the power storage module group 1510 has one or more power storage modules 110 connected in parallel. In this embodiment, the power storage module group 1530 has one or more power storage modules 130 connected in parallel. At least one of the multiple power storage modules 130 constituting the power storage module group 1530 may be the power storage module 1630 shown in FIG. 16. At least two of the multiple power storage modules 130 constituting the power storage module group 1530 may be the power storage module 1630 shown in FIG. 16. Of the multiple power storage modules 130 constituting the power storage module group 1530, the storage module having the largest set value of the charging end voltage may be the power storage module 1630.

[0332] 16, the power storage module 1630 differs from the power storage module 1430 in that it includes a short-circuit switch 1632 and a module control unit 1640 instead of the module control unit 1040. Other than the above differences, the power storage module 1630 may have the same configuration as the power storage module 1430.

[0333] In this embodiment, the shorting switch 1632 is disposed between the wiring 106 and the power storage unit 210. The shorting switch 1632 is connected in parallel with the switching unit 230 between the wiring 106 and the power storage unit 210. In this embodiment, the shorting switch 1632 shorts the switching unit 230. For example, the ON operation of the shorting switch 1632 transitions the shorting switch 1632 to a state in which the shorting switch 1632 shorts the switching unit 230.

[0334] In this embodiment, the shorting switch 1632 switches between a state in which the shorting switch 1632 shorts the switching unit 230 and a state in which the shorting switch 1632 does not short the switching unit 230. The shorting switch 1632 may switch between a state in which the shorting switch 1632 shorts the switching unit 230 and a state in which the shorting switch 1632 does not short the switching unit 230 based on an instruction from the module control unit 1640. This allows the shorting switch 1632 to short the switching unit 230 as necessary. Note that the shorting switch 1632 may switch the state of the shorting switch 1632 based on a signal from an element or circuit other than the module control unit 1640.

[0335] In one embodiment, when it is detected that the output current of the power storage system 100 is larger than the charging current of the power storage system 100, or when it is expected that the output current of the power storage system 100 will be larger than the charging current of the power storage system 100, the shorting switch 1632 receives an instruction to short-circuit the switching unit 230. For example, when the system control unit 140 acquires information (sometimes referred to as a notice signal) indicating that the load device 20 will start using power from the load device 20, the shorting switch 1632 receives an instruction to turn the shorting switch 1632 ON. The instruction to turn the shorting switch 1632 ON may be an example of an instruction to short-circuit the switching unit 230.

[0336] In another embodiment, the shorting switch 1632 receives an instruction to turn off the shorting switch 1632 in at least one of the following cases: (i) when a predetermined period has elapsed since the shorting switch 1632 shorted the switching unit 230, and (ii) when it is detected that the output current of the power supply system 10 is smaller than the charging current of the power supply system 10, or when it is predicted that the output current of the power supply system 10 will become smaller than the charging current of the power supply system 10. The instruction to turn off the shorting switch 1632 may be an example of an instruction to switch the state of the shorting switch 1632 from a state in which the shorting switch 1632 shorts the switching unit 230 to a state in which the shorting switch 1632 does not short the switching unit 230.

[0337] In this embodiment, the module control unit 1640 differs from the module control unit 1040 in that the module control unit 1640 controls the operation of the shorting switch 1632. Other than the above differences, the module control unit 1640 may have the same configuration as the module control unit 1040.

[0338] In one embodiment, when it is detected that the output current of the power supply system 10 is greater than the charging current of the power supply system 10, or when it is detected that the output current of the power supply system 10 will become greater than the charging current of the power supply system 10, the module control unit 1640 decides to short-circuit the switching unit 230. For example, when the system control unit 140 acquires information (sometimes referred to as a notice signal) indicating that the load device 20 will start using power from the load device 20, the module control unit 1640 decides to short-circuit the switching unit 230. When the module control unit 1640 decides to short-circuit the switching unit 230, the module control unit 1640 generates an instruction to turn on the short-circuiting switch 1632 and transmits the instruction to the short-circuiting switch 1632.

[0339] In another embodiment, in at least one of the cases where (i) a predetermined period has elapsed since the shorting switch 1632 shorted the switching unit 230, and (ii) it is detected that the output current of the power supply system 10 is smaller than the charging current of the power supply system 10 or that the output current of the power supply system 10 will become smaller than the charging current of the power supply system 10, the module control unit 1640 decides not to short-circuit the switching unit 230. In addition, the module control unit 1640 generates an instruction to turn off the shorting switch 1632 and transmits the instruction to the shorting switch 1632.

[0340] The power storage system 1500 may be an example of a power storage system. The power storage module group 1510 may be an example of a second power storage device. The power storage module group 1530 may be an example of a first power storage device. The power storage module 1630 may be an example of a first power storage device. The short-circuit switch 1632 may be an example of a short-circuit unit and a short-circuit state switching unit.

[0341] In the present embodiment, the details of the storage module 1630 have been described by taking as an example a case where the storage module 1430 and the storage module 1630 are partially different. However, the storage module 1630 is not limited to the present embodiment. In other embodiments, the storage module 1630 can be manufactured by modifying a portion of the storage module 1330 so that the storage module 1330 has features related to the differences between the storage module 1430 and the storage module 1630.

[0342] Next, an example of the operation of the power supply system 10 including the power storage module group 1530 having at least one power storage module 1630 will be described with reference to Fig. 17 and Fig. 18. In the description relating to Fig. 17 and Fig. 18, for the purpose of simplifying the description, an example of the operation of the power supply system 10 will be described taking as an example a case in which the power storage module 1630 is the power storage module having the largest set value of the charging end voltage among the multiple power storage modules 130 constituting the power storage module group 1530.

[0343] Fig. 17 illustrates an example of control by the module control unit 1640. Fig. 17 illustrates an example of fluctuation 1722 in the ON / OFF state of the notice signal, an example of fluctuation 1724 in the output current of the power supply system 10, an example of fluctuation 1732 in the ON / OFF state of the shorting switch 1632, an example of fluctuation 1734 in the state of the switching unit 230, and an example of fluctuation 1740 in the output voltage of the power supply system 10.

[0344] Fig. 18 shows an example of current fluctuations in each part of the power supply system 10. Fig. 18 shows an example of charge current fluctuations 1822 of the power storage system 1500, and an example of current fluctuations 1824 of the power storage module having the highest voltage in the power storage module group 1530. In this embodiment, the power storage module is the power storage module 1630.

[0345] 17 and 18, according to this embodiment, trickle charging of the power storage module group 1530 is performed in a period before time t1. At this time, a voltage of Vcv [V] is applied to the power storage module 1630, and a current of Ict [A] flows through it. In this embodiment, at this time, the switching units 230 of all the power storage modules attached to the power storage system 150 electrically disconnect the wiring 106 of each power storage module from the power storage unit 210. In addition, the current supplied from the charging device 14 to each power storage module flows into the power storage unit 210 via the trickle charging unit 320.

[0346] Here, at time t1, the module control unit 1640 detects that the notice signal has turned ON. When the notice signal turns ON, the module control unit 1640 turns ON the short-circuiting switch 1632 of the power storage module 1630. When the short-circuiting switch 1632 turns ON, the terminal voltage of the power supply system 10 becomes approximately equal to the terminal voltage Von [V] of the power storage module 1630. After the notice signal turns ON or the short-circuiting switch 1632 turns ON, the charging device 14 may increase the amount of power or current provided to the power storage system 1500 to Icc.

[0347] Thereafter, at time t2, the switching unit 230 turns ON. According to one embodiment, when the terminal voltage of the power supply system 10 becomes substantially equal to the terminal voltage Von [V] of the power storage module 1630, the module control unit 1640 turns ON the switching unit 230 at time t2. According to another embodiment, the module control unit 1640 transmits a reset signal to the protection unit 250. This disables the overcharge protection function of the protection unit 250, and the switching unit 230 turns ON at time t2.

[0348] Through the above operations, the power supply system 10 is ready to stably supply power. After that, at time t3, the load device 20 starts consuming power. At this time, the magnitude of the output current of the power supply system 1910 is Iout [A]. Iout may be a value larger than a predetermined value.

[0349] Generally, a delay occurs between when the notice signal turns ON and when the switching unit 230 turns ON. Therefore, for example, if the load device 20 consumes a large amount of power while all the power storage modules mounted in the power storage system 150 are electrically disconnected from the wiring 106, the voltage between the terminals of the power supply system 10 decreases rapidly, and the ON operation of the switching unit 230 may not be completed in time.

[0350] In contrast, according to the present embodiment, the connection between at least one power storage module 1630 and the wiring 106 of the power storage system 1500 is completed before the load device 20 starts consuming power. As a result, the power supply system 10 can stably supply power. In the present embodiment, the length of the ON time ts of the notice signal may be set to a value greater than the length of the period tb between the time the notice signal turns ON and the time the load device 20 starts consuming power. In addition, the length of the period tb may be set to a value greater than the length of the delay time td of the switching unit 230.

[0351] [Other examples of power supply systems] Another example of the power supply system will be described with reference to Fig. 19, Fig. 20, and Fig. 21. Fig. 19 shows an example of the system configuration of a power supply system 1910. Fig. 20 shows an example of control by a module control unit 1640. Fig. 21 shows an example of current fluctuations in each unit of the power supply system 1910.

[0352] As shown in FIG. 19, the power supply system 1910 differs from the power supply system 10 described in relation to FIGS. 15 and 16 in that it further includes a capacitor 1920 and in that the power supply system 1910 does not necessarily need to short-circuit the switching unit 230 before outputting current.

[0353] 17 and 18, the shorting switch 1632 shorts the switching unit 230 before the power supply system 10 outputs a current, thereby stabilizing the power supply from the power supply system 10 to the load device 20. On the other hand, according to the present embodiment, the capacitor 1920 is connected in parallel with the load device 20, thereby suppressing abrupt fluctuations in the output voltage of the power supply system 1910. This can stabilize the power supply from the power supply system 10 to the load device 20.

[0354] For example, since a sudden change in the output voltage of the power supply system 1910 is suppressed, the switching unit 230 can easily respond to a decrease in the output voltage of the power supply system 1910. Even if the switching unit 230 cannot respond to a decrease in the output voltage of the power supply system 1910, the shorting switch 1632 can short-circuit the switching unit 230 in response to the system control unit 140 receiving a notification signal indicating that the load device 20 has started consuming power. As a result, the power supply from the power supply system 10 to the load device 20 can be stabilized. In this embodiment, the shorting switch 1632 may short-circuit the switching unit 230 before the power supply system 10 outputs a current, or may short-circuit the switching unit 230 after the power supply system 10 outputs a current.

[0355] According to this embodiment, for example, one end of the capacitor 1920 is electrically connected to the connection terminal 102, and the other end of the capacitor 1920 is electrically connected to the connection terminal 104. As a result, when the load device 20 is electrically connected to the power supply system 1910, the capacitor 1920 and the load device 20 are connected in parallel. As a result, fluctuations in the output voltage of the power supply system 1910 are suppressed. Therefore, for example, even if the load device 20 consumes a large amount of power in a state where all the power storage modules attached to the power storage system 150 are electrically disconnected from the wiring 106, the ON operation of the switching unit 230 can respond to a drop in the voltage of the wiring 106.

[0356] The power supply system 1910 may be an example of a power storage system. The capacitor 1920 may be an example of a fluctuation suppression unit.

[0357] FIG. 20 shows an example of a fluctuation 2022 in the ON / OFF state of the notification signal, an example of a fluctuation 2024 in the output current of the power supply system 10, an example of a fluctuation 2032 in the ON / OFF state of the shorting switch 1632, an example of a fluctuation 2034 in the state of the switching unit 230, and an example of a fluctuation 2040 in the output voltage of the power supply system 10.

[0358] The notification signal may be a signal indicating that the load device 20 has started consuming current or that the load device 20 is consuming current. The notification signal may be a signal indicating that the current value of the current consumed by the load device 20 is equal to or greater than a predetermined value. The notification signal is transmitted from the load device 20 to the system control unit 140, for example.

[0359] 21 shows an example of a fluctuation 2122 in the charging current of the power storage system 1500 and an example of a fluctuation 2124 in the current of a storage module having the highest voltage in the storage module group 1530. As described above, the storage module group 1530 includes one or more storage modules 1630. In this embodiment, the storage module having the highest voltage may be the storage module 1630.

[0360] 20 and 21, according to this embodiment, trickle charging of the power storage module group 1530 is performed in a period before time t1. At this time, a voltage of Vcv [V] is applied to the power storage module 1630, and a current of Ict [A] flows through it. In this embodiment, at this time, the switching units 230 of all the power storage modules attached to the power storage system 150 electrically disconnect the wiring 106 of each power storage module from the power storage unit 210. In addition, the current supplied from the charging device 14 to each power storage module flows into the power storage unit 210 via the trickle charging unit 320.

[0361] Here, at time t1, the load device 20 starts consuming power. At this time, the magnitude of the output current of the power supply system 1910 is Iout [A]. Iout may be a value larger than a predetermined value. When the load device 20 starts consuming power, the output voltage of the power supply system 1910 decreases. After the load device 20 starts consuming power, the charging device 14 may increase the amount of power or current provided to the power storage system 1500 to Icc. At this time, if the capacity of the capacitor 1920 is C and the magnitude of the output current of the power supply system 1910 is I2, in FIG. 20, the rate of decrease in the output voltage is represented by a slope of (I2-Icc) / C.

[0362] Next, at time t2, the module control unit 1640 detects that the notification signal has been turned ON. When the notification signal is turned ON, the module control unit 1640 turns ON the short-circuiting switch 1632 of the power storage module 1630. As described above, the above-mentioned power storage module 1630 has the highest terminal voltage among the power storage modules included in the power storage module group 1530. Therefore, when the short-circuiting switch 1632 is turned ON, the terminal voltage of the power supply system 10 becomes approximately equal to the terminal voltage Von [V] of the above-mentioned power storage module 1630.

[0363] At this time, a large battery current I Aflows. This charges the capacitor 1920. This causes the voltage across the terminals of the power supply system 10 to increase.

[0364] Thereafter, when the delay time td has elapsed from time t2 and it becomes time t3, the switching unit 230 of the above-mentioned power storage module 1630 is turned ON. At this time, the output voltage of the power supply system 1910 becomes Vout [V]. The magnitude of Vout [V] is determined by, for example, the power storage module group 1530.

[0365] In this embodiment, the length of the ON time ts of the notification signal may be set to a value greater than the length of the delay time td of the switching unit 230. The length of the period tb between the start time of power consumption of the load device 20 and the time the notification signal turns ON may be determined based on the capacitance of the capacitor 1920.

[0366] [Other examples of power supply systems] Another example of the power supply system will be described with reference to Fig. 22, Fig. 23, and Fig. 24. Fig. 22 shows an example of the system configuration of a power supply system 2210. Fig. 23 shows an example of control by the module control unit 1640. Fig. 24 shows an example of current fluctuations in each part of the power supply system 2210.

[0367] 22, the power supply system 2210 differs from the power supply system 10 described with reference to Fig. 15 and Fig. 16 in that the power supply system 2210 further includes a current detection element 2220 and that the shorting switch 1632 shorts the switching unit 230 based on the detection result of the current detection element 2220. Regarding other features, the power supply system 2210 may have a similar configuration to the power supply system 10 described with reference to Fig. 15 and Fig. 16.

[0368] In this embodiment, the current detection element 2220 detects that the power supply system 2210 has supplied power to the load device 20. In addition, the current detection element 2220 transmits information indicating the detection result to the system control unit 140.

[0369] In one embodiment, the current detection element 2220 detects whether the output current of the power supply system 2210 is greater than a predetermined value. If it is detected that the output current of the power supply system 2210 is greater than the predetermined value, the current detection element 2220 transmits information indicating the detection result to the system control unit 140. In another embodiment, the current detection element 2220 measures the current value of the output current of the power supply system 2210. The current detection element 2220 transmits information indicating the measurement result to the system control unit 140.

[0370] In this embodiment, when the system control unit 140 detects that the power supply system 2210 has supplied power to the load device 20, it transmits to the module control unit 1640 (i) a signal indicating that it has been detected that the power supply system 2210 has supplied power to the load device 20 (sometimes referred to as a detection signal), or (ii) a signal to turn on the short-circuit switch 1632.

[0371] In this embodiment, when the module control unit 1640 receives a detection signal or a signal for turning on the shorting switch 1632, the module control unit 1640 transmits a signal for turning on the shorting switch 1632 to the shorting switch 1632. This shorts the switching unit 230. When the current detection element 2220 detects that the power supply system 2210 has supplied power to the load device 20, the switching unit 230 is shorted.

[0372] FIG. 23 shows an example of a fluctuation 2322 in the ON / OFF state of the detection signal, an example of a fluctuation 2324 in the output current of the power supply system 10, an example of a fluctuation 2332 in the ON / OFF state of the shorting switch 1632, an example of a fluctuation 2334 in the state of the switching unit 230, and an example of a fluctuation 2340 in the output voltage of the power supply system 10.

[0373] 24 illustrates an example of a fluctuation 2422 in the charging current of the power storage system 1500 and an example of a fluctuation 2424 in the current of a storage module having the highest voltage in the power storage module group 1530. As described above, the power storage module group 1530 includes one or more storage modules 1630. In this embodiment, the storage module having the highest voltage may be the storage module 1630.

[0374] 23 and 24, according to this embodiment, trickle charging of the power storage module group 1530 is performed in a period before time t1. At this time, a voltage of Vcv [V] is applied to the power storage module 1630, and a current of Ict [A] flows through it. In this embodiment, at this time, the switching units 230 of all the power storage modules attached to the power storage system 150 electrically disconnect the wiring 106 of each power storage module from the power storage unit 210. In addition, the current supplied from the charging device 14 to each power storage module flows into the power storage unit 210 via the trickle charging unit 320.

[0375] On the other hand, at time t0, the load device 20 starts consuming power. In this embodiment, after the power supply system 2210 supplies power to the load device 20, the current consumption of the load device 20 increases continuously or stepwise. According to this embodiment, the value of the output current of the power supply system 2210 increases continuously as time passes.

[0376] Then, at time t1, the current value of the power supply system 2210 reaches Isp [A]. Isp may be a predetermined value. When the current value of the power supply system 2210 reaches Isp [A], the current detection element 2220 detects the output current of the power supply system 2210. This detects that the power supply system 2210 has supplied power to the load device 20.

[0377] When the detection signal is turned ON, the module control unit 1640 turns ON the short-circuiting switch 1632 of the power storage module 1630. When the short-circuiting switch 1632 is turned ON, the terminal voltage of the power supply system 10 becomes approximately equal to the terminal voltage Von [V] of the power storage module 1630. After the short-circuiting switch 1632 is turned ON, the charging device 14 may increase the amount of power or current provided to the power storage system 1500 up to Icc.

[0378] Thereafter, when delay time td has elapsed from time t1 to time t2, the switching unit 230 turns ON. In this embodiment, when time ta has elapsed after the short-circuiting switch 1632 turns ON, the module control unit 1640 turns OFF the short-circuiting switch 1632 of the power storage module 1630. The length of time ta may be set to a value greater than the length of delay time td of the switching unit 230.

[0379] The power supply system 2210 may be an example of a power storage system. The current detection element 2220 may be an example of a detection unit.

[0380] Although the present invention has been described above using the embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It is clear to those skilled in the art that various modifications or improvements can be made to the above embodiments. In addition, the matters described for a specific embodiment can be applied to other embodiments to the extent that they are not technically inconsistent. It is clear from the claims that such modified or improved forms can also be included in the technical scope of the present invention.

[0381] It should be noted that the order of execution 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 indicated as "before," "prior to," etc., and may be realized in any order unless the output of a previous process is used in a later process. Even if the operational flow in the claims, specifications, and drawings is explained using "first," "next," etc. for convenience, it does not mean that it is essential to perform the process in this order. [Explanation of symbols]

[0382] 10 power supply system, 14 charging device, 16 charging switching unit, 20 load device, 26 load switching unit, 52 signal, 54 signal, 86 signal, 88 signal, 100 power storage system, 102 connection terminal, 104 connection terminal, 106 wiring, 110 power storage module, 130 power storage module, 140 system control unit, 150 power storage system, 202 positive terminal, 204 negative terminal, 210 power storage unit, 212 positive terminal, 214 negative terminal, 222 power storage cell, 224 power storage cell, 230 switching unit, 240 module control unit, 250 protection unit, 260 balance correction unit, 320 trickle charging unit, 322 direction restriction unit, 324 flow rate restriction unit, 410 determination unit, 420 receiving unit, 430 signal generation unit, 440 Module information acquisition unit, 450, module information storage unit, 460, module information transmission unit, 510, transistor, 512, resistor, 514, resistor, 516, diode, 520, transistor, 522, resistor, 524, resistor, 526, diode, 530, transistor, 532, resistor, 540, transistor, 542, resistor, 552, resistor, 554, resistor, 560, transistor, 570, capacitor, 572, resistor, 580, transistor, 592, switch, 594, switch, 622, state management unit, 624, module selection unit, 626, signal generation unit, 642, charge control unit, 644, charge unit, 662, load control unit, 664, load unit, 710, fluctuation, 730, fluctuation, 740, fluctuation, 814, fluctuation, 914, output characteristic, 1010, power storage module, 1020 Current detection element, 1040 module control unit, 1120 current monitoring unit, 1122 current detection unit, 1124 direction determination unit, 1242 parasitic diode, 1244 parasitic diode, 1260 OR circuit, 1272 AND circuit, 1274 AND circuit, 1282 OR circuit, 1284 OR circuit, 1330 power storage module, 1430 power storage module, 1500 power storage system, 1510 power storage module group, 1530 power storage module group, 1630 power storage module, 1632 short-circuit switch, 1640 module control unit, 1722 fluctuation, 1724 fluctuation, 1732 fluctuation, 1734 fluctuation, 1740 fluctuation, 1822 fluctuation, 1824 fluctuation, 1910 power supply system, 1920 capacitor, 2022 fluctuation, 2024 Change, 2032fluctuation, 2034 fluctuation, 2040 fluctuation, 2122 fluctuation, 2124 fluctuation, 2210 power supply system, 2220 current sensing element, 2322 fluctuation, 2324 fluctuation, 2332 fluctuation, 2334 fluctuation, 2340 fluctuation, 2422 fluctuation, 2424 fluctuation

Claims

1. A power storage system including wiring for connecting in parallel a first power storage device having a first power storage unit and a second power storage device having a second power storage unit, The first power storage device is a first switching unit that is disposed between the wiring and the first power storage unit and that switches an electrical connection relationship between the wiring and the first power storage unit based on a voltage difference between the wiring and the first power storage unit; having The second power storage device is a second switching unit that is disposed between the wiring and the second power storage unit and that switches an electrical connection relationship between the wiring and the second power storage unit based on a voltage difference between the wiring and the second power storage unit; having the first power storage unit includes a first type of secondary battery, the second power storage unit includes a second type of secondary battery, a battery system of the first type of secondary battery is represented by a reaction formula that, in principle, does not cause irreversible changes in the battery system even if an overcharged state is sustained; The battery system of the second type of secondary battery is represented by a reaction formula in which, in principle, an irreversible change occurs in the battery system when an overcharged state continues, The charge end voltage of the first power storage unit is The voltage is equal to or lower than a fully charged voltage of the first power storage unit, and is greater than the end-of-charge voltage of the second storage unit, The first power storage device is a limiting section connected in parallel with the first switching section between the wiring and the first power storage unit, having a resistance greater than that of the first switching section, allowing a current to pass in a direction from the wiring to the first power storage unit and suppressing a current from passing in a direction from the first power storage unit to the wiring and a current supplied from a charging device that charges the first power storage device and the second power storage device, which are connected in parallel, in a state in which the first switching unit electrically disconnects the wiring from the first power storage unit and the second switching unit electrically disconnects the wiring from the second power storage unit flows into the first power storage device via the limiting unit; Energy storage system.

2. When the first switching unit electrically disconnects the wiring from the first power storage unit and the second switching unit electrically disconnects the wiring from the second power storage unit, a current supplied from a charging device that charges the first power storage device and the second power storage device connected in parallel flows into the first power storage device via the limiting unit and does not flow into the second power storage device. The power storage system according to claim 1 .

3. a full charge voltage of the first power storage unit is lower than a charging voltage of a charging device that charges the first power storage device and the second power storage device that are connected in parallel, The power storage system according to claim 1 or 2.

4. A charging voltage control unit that controls a set value of the charging voltage of the charging device is further provided. The power storage system according to claim 3 .

5. the charging device charges the first power storage device and the second power storage device by a constant current method during at least a part of a charging period of the first power storage device and the second power storage device; The power storage system according to claim 3 or 4.

6. The charging device is When the voltage of the first power storage unit is equal to or lower than a charging end voltage, the first power storage unit is charged by a constant current method; When the voltage of the first power storage unit is greater than a charging end voltage, the first power storage unit is charged by a trickle charging method. The power storage system according to any one of claims 3 to 5.

7. A power storage system comprising wiring for connecting in parallel a first power storage device having a first power storage unit and a second power storage device having a second power storage unit, The first power storage device is a first switching unit that is disposed between the wiring and the first power storage unit and that switches an electrical connection relationship between the wiring and the first power storage unit based on a voltage difference between the wiring and the first power storage unit; having The second power storage device is a second switching unit that is disposed between the wiring and the second power storage unit and that switches an electrical connection relationship between the wiring and the second power storage unit based on a voltage difference between the wiring and the second power storage unit; having the first power storage unit includes a first type of secondary battery, the second power storage unit includes a second type of secondary battery, a battery system of the first type of secondary battery is represented by a reaction formula that, in principle, does not cause irreversible changes in the battery system even if an overcharged state is sustained; The battery system of the second type of secondary battery is represented by a reaction formula in which, in principle, an irreversible change occurs in the battery system when an overcharged state continues, The charge end voltage of the first power storage unit is The voltage is equal to or lower than a fully charged voltage of the first power storage unit, and is greater than the end-of-charge voltage of the second storage unit, a full charge voltage of the first power storage unit is lower than a charging voltage of a charging device that charges the first power storage device and the second power storage device that are connected in parallel, The first power storage device is a limiting section connected in parallel with the first switching section between the wiring and the first power storage unit, having a resistance greater than that of the first switching section, allowing a current to pass in a direction from the wiring to the first power storage unit and suppressing a current from passing in a direction from the first power storage unit to the wiring and The charging device is When the voltage of the first power storage unit is equal to or lower than a charging end voltage, the first power storage unit is charged by a constant current method; When the voltage of the first power storage unit is higher than a charge end voltage, the first power storage unit is charged by a trickle charge method via the limiting unit. Energy storage system.

8. A power storage system comprising wiring for connecting in parallel a first power storage device having a first power storage unit and a second power storage device having a second power storage unit, The first power storage device is a first switching unit that is disposed between the wiring and the first power storage unit and that switches an electrical connection relationship between the wiring and the first power storage unit based on a voltage difference between the wiring and the first power storage unit; having The second power storage device is a second switching unit that is disposed between the wiring and the second power storage unit and that switches an electrical connection relationship between the wiring and the second power storage unit based on a voltage difference between the wiring and the second power storage unit; having the first power storage unit includes a first type of secondary battery, the second power storage unit includes a second type of secondary battery, a battery system of the first type of secondary battery is represented by a reaction formula that, in principle, does not cause irreversible changes in the battery system even if an overcharged state is sustained; The battery system of the second type of secondary battery is represented by a reaction formula in which, in principle, an irreversible change occurs in the battery system when an overcharged state continues, The charge end voltage of the first power storage unit is The voltage is equal to or lower than a fully charged voltage of the first power storage unit, and is greater than the end-of-charge voltage of the second storage unit, The first power storage device is a limiting section connected in parallel with the first switching section between the wiring and the first power storage unit, having a resistance greater than that of the first switching section, allowing a current to pass in a direction from the wiring toward the first power storage unit and suppressing a current from passing in a direction from the first power storage unit toward the wiring and the second power storage unit is connected in parallel with the second switching unit between the wiring and the second power storage unit, has a resistance greater than that of the second switching unit, and passes a current in a direction from the wiring to the second power storage unit, and does not have a limiting unit that suppresses the current from passing in a direction from the second power storage unit to the wiring. Energy storage system.

9. The limiting unit of the first power storage device is a current amount limiting unit that limits the amount of current flowing through the limiting unit included in the first power storage device; a current direction limiting unit connected in series with the current amount limiting unit, allowing a current to pass in a direction from the wiring to the first power storage unit and not allowing a current to pass in a direction from the first power storage unit to the wiring; Including, The power storage system according to any one of claims 1 to 8.

10. A power storage system comprising wiring for connecting in parallel a first power storage device having a first power storage unit and a second power storage device having a second power storage unit, The first power storage device is a first switching unit that is disposed between the wiring and the first power storage unit and that switches an electrical connection relationship between the wiring and the first power storage unit based on a voltage difference between the wiring and the first power storage unit; having The second power storage device is a second switching unit that is disposed between the wiring and the second power storage unit and that switches an electrical connection relationship between the wiring and the second power storage unit based on a voltage difference between the wiring and the second power storage unit; having the first power storage unit includes a first type of secondary battery, the second power storage unit includes a second type of secondary battery, a battery system of the first type of secondary battery is represented by a reaction formula that, in principle, does not cause irreversible changes in the battery system even if an overcharged state is sustained; The battery system of the second type of secondary battery is represented by a reaction formula in which, in principle, an irreversible change occurs in the battery system when an overcharged state continues, The charge end voltage of the first power storage unit is The voltage is equal to or lower than a fully charged voltage of the first power storage unit, and is greater than the end-of-charge voltage of the second storage unit, The first power storage device is a short-circuiting portion that is arranged between the wiring and the first power storage portion, that is connected in parallel to the first switching portion between the wiring and the first power storage portion, and that short-circuits the first switching portion; and The short circuit portion is a short-circuit state switching unit that switches the short-circuit unit to a state in which the short-circuit unit shorts the first switching unit; Including, the short-circuit state switching unit shorts the first switching unit when it is detected that the output current of the power storage system is larger than the charging current of the power storage system, or when it is predicted that the output current of the power storage system will be larger than the charging current of the power storage system. Energy storage system.

11. The short circuit state switching unit is (i) a predetermined period of time has elapsed since the short-circuit state switching unit shorted the first switching unit, and (ii) at least one of a case where it is detected that the output current of the power storage system is smaller than the charging current of the power storage system or a case where it is predicted that the output current of the power storage system will become smaller than the charging current of the power storage system, switching a state of the short-circuiting portion from a state in which the short-circuiting portion shorts the first switching portion to a state in which the short-circuiting portion does not short-circuit the first switching portion; The power storage system according to claim 10.

12. The short circuit state switching unit is When the power storage system acquires information indicating that a load device that uses power supplied from the power storage system starts using power, The first switching unit is short-circuited. The power storage system according to claim 10 or 11.

13. The short-circuit state switching unit shorts the first switching unit before the power storage system outputs a current. The power storage system according to any one of claims 10 to 12.

14. A fluctuation suppressing unit is further provided for suppressing fluctuations in the output voltage of the power storage system. The power storage system according to any one of claims 10 to 13.

15. The short-circuit state switching unit shorts the first switching unit after the power storage system outputs a current. The power storage system according to claim 14.

16. the fluctuation suppression unit is arranged such that, when a load device that uses power supplied from the power storage system is electrically connected to the power storage system, the fluctuation suppression unit and the load device are connected in parallel; The power storage system according to claim 15.

17. A detection unit that detects that the power storage system has supplied power to a load device, The short circuit state switching unit is When the detection unit detects that the power storage system has supplied power to a load device, The first switching unit is short-circuited. The power storage system according to any one of claims 10 to 16.

18. After the power storage system supplies power to the load device, the current consumption of the load device increases continuously or stepwise. The power storage system according to claim 17.

19. The power storage system includes: receiving a request signal from the load device indicative of a magnitude of current to be supplied to the load device; outputting a current of a magnitude indicated by said demand signal; The power storage system according to claim 18.

20. The load device includes a current consumption control unit that controls the amount of current consumption of the load device. The power storage system according to claim 18.

21. the power storage system includes a plurality of the first power storage devices connected in parallel, At least two of the plurality of first power storage devices have the short-circuit portion. The power storage system according to any one of claims 10 to 20.

22. The first storage device; The second power storage device; Further comprising: The power storage system according to any one of claims 1 to 21.

Images