JP7793182B2 - Energy storage system, power system, control method, and program - Google Patents

Description

The present invention relates to switching control devices, current control devices, power storage devices, power transfer systems, and power systems.

In a power storage system including a plurality of power storage modules, the power storage modules may be connected in parallel (see, for example, Patent Document 1). Patent Document 2 discloses a power storage system in which power storage modules can be hot-plugged.
[Prior art documents]
[Patent Documents]
[Patent Document 1] JP-A-11-98708 [Patent Document 2] WO 2017/086349

In recent years, as energy storage systems have become larger in scale, energy storage modules have become increasingly higher in voltage. As the storage voltage of a storage module increases, arc discharge can occur inside the contactor or relay when a contactor or relay is operated while current is flowing through the storage module to electrically disconnect the storage module from the energy storage system. Arc discharge can cause the contactor or relay to fail.

A first aspect of the present invention provides a switching control device. The switching control device controls, for example, the operation of a switching device. In the switching control device, the switching device switches the electrical connection state between, for example, a power storage unit of a power storage device and a power terminal of the power storage device. The switching control device includes, for example, a first determination unit that determines whether the voltage of the power storage unit has reached a predetermined first threshold. The switching control device includes, for example, a first signal output unit that outputs a first signal to notify the user that the power storage unit and the power terminal will be electrically disconnected when it is determined that the voltage of the power storage unit has reached the first threshold. The switching control device includes, for example, a second signal output unit that outputs, to the switching device, a second signal to electrically disconnect the power storage unit and the power terminal when a disconnection permission condition, which is a condition for permitting the electrical disconnection of the power storage unit and the power terminal, is met after the first signal output unit outputs the first signal.

In the above switching control device, the energy storage unit may have a plurality of energy storage cells connected in series. In the above switching control device, the first determination unit may determine that the voltage of the energy storage unit has reached the first threshold when the voltage of at least one of the plurality of energy storage cells reaches the first threshold. In the above switching control device, the first threshold may be (i) a value obtained by subtracting a predetermined value from the fully charged voltage of at least one energy storage cell, or (ii) a value obtained by adding a predetermined value to the end-of-discharge voltage of at least one energy storage cell.

In the above-described switching control device, the disconnection permission condition may include at least one of the following conditions: (i) a predetermined time has elapsed after the first signal output unit outputs the first signal; (ii) a process has been executed to reduce the magnitude of the current flowing through the switching device below a predetermined second threshold value after the first signal output unit outputs the first signal; (iii) the first signal output unit outputs the first signal, and the magnitude of the current flowing through the switching device is less than the second threshold value; and (iv) the first signal output unit outputs the first signal, and electrical disconnection of the power storage unit and the power terminal is not prohibited or is permitted.

The above-mentioned switching control device may include a third signal output unit that, when the first signal output unit outputs the first signal, outputs a third signal to an adjustment device that adjusts the magnitude of the current flowing through the switching device, for reducing the magnitude of the current flowing through the switching device below a predetermined second threshold. In the above-mentioned switching control device, the adjustment device may be (i) a unidirectional or bidirectional DC/DC converter, (ii) a unidirectional or bidirectional DC/AC inverter, or (iii) an on/off switch. In the above-mentioned switching control device, the power terminal of the adjustment device may be electrically connected to the power terminal of the power storage device.

In a second aspect of the present invention, a power storage device is provided. The power storage device includes, for example, the switching control device according to the first aspect. The power storage device includes, for example, a power storage unit. The power storage device includes, for example, a power terminal.

In a third aspect of the present invention, a power transfer system is provided. The power transfer system includes, for example, the power storage device according to the second aspect. The power transfer system includes, for example, another power transfer device different from the power storage device. In the power transfer system, for example, the power storage device is configured to be detachable from the wiring for connecting the power storage device and the other power transfer device in parallel.

A fourth aspect of the present invention provides a current control device. The current control device includes a third signal output unit that, when receiving a first signal indicating that the power storage device and an adjustment device that adjusts the magnitude of the current flowing through the power storage device will be electrically disconnected, outputs a third signal to the adjustment device to reduce the magnitude of the current flowing through the power storage device below a predetermined second threshold.

In a fifth aspect of the present invention, there is provided a power transfer system. The power transfer system includes, for example, the current control device according to the fourth aspect. The power transfer system includes, for example, a power storage device. The power transfer system includes, for example, another power transfer device different from the power storage device. The power transfer system includes, for example, wiring for connecting the power storage device and the other power transfer device in parallel. The power transfer system includes, for example, an adjustment device.

In the above-mentioned power transfer system, the power storage device is configured to be detachable from the wiring, for example. The power storage device transfers power to and from an external device located outside the power transfer system, for example, via an adjustment device. The above-mentioned power transfer system may include the switching control device according to the first aspect described above.

A sixth aspect of the present invention provides an electric power system. The electric power system includes, for example, a plurality of electric power transfer systems according to the fifth aspect. In the electric power system, the first signal is, for example, a signal for notifying the user that a power storage device and an adjustment device of a first electric power transfer system included in the plurality of electric power transfer systems will be electrically disconnected. In the electric power system, the current control device of the first electric power transfer system has, for example, a second determination unit that determines whether the magnitude of the output current of the first electric power transfer system may be reduced below a second threshold value based on the state of at least one second electric power transfer system included in the plurality of electric power transfer systems. In the electric power system, the third signal output unit of the first electric power transfer system outputs a third signal, for example, when the second determination unit determines that the magnitude of the output current of the first electric power transfer system may be reduced below the second threshold value. In the electric power system, each of the at least one second electric power transfer system is, for example, a different electric power transfer system from the first electric power transfer system.

In the above-described power system, the current control device of at least one second power transfer system may include a fourth signal output unit that outputs a fourth signal to the adjustment device of at least one second power transfer system to increase the magnitude of the output current of the at least one second power transfer system when the second determination unit determines that the magnitude of the output current of the first power transfer system may be reduced below the second threshold.

A seventh aspect of the present invention provides a control method for a switching device. The switching device, for example, switches the electrical connection state between an electric storage device of an electric storage device and a power terminal of the electric storage device. The control method, for example, includes a first determination step of determining whether the voltage of the electric storage device has reached a predetermined first threshold. The control method, for example, includes a first signal output step of outputting a first signal to notify the electric storage device and the power terminal that they will be electrically disconnected when it is determined that the voltage of the electric storage device has reached the first threshold. The control method, for example, includes a second signal output step of outputting a second signal to the switching device to electrically disconnect the electric storage device and the power terminal when a disconnection permission condition, which is a condition for permitting the electric disconnection of the electric storage device and the power terminal, is met after the first signal is output in the first signal output step.

An eighth aspect of the present invention provides a control method. The control method includes, for example, a third signal output step of outputting a third signal to the adjustment device, when a first signal is received to notify that the power storage device and the adjustment device that adjusts the magnitude of the current flowing through the power storage device will be electrically disconnected, to the adjustment device, for reducing the magnitude of the current flowing through the power storage device below a predetermined second threshold.

In a ninth aspect of the present invention, a program is provided. The program may be a program for causing a computer to function as the switching control device according to the first aspect. The program may be a program for causing a computer to function as the current control device according to the fourth aspect. The program may be a program for causing a computer to execute the control method according to the seventh or eighth aspect. A non-transitory computer-readable medium for storing the program may be provided.

Note that the above summary of the invention does not list all of the necessary features of the present invention. Subcombinations of these features may also constitute inventions.

1 shows an example of a system configuration of a power storage system 100. 2 shows an example of a system configuration of a power storage module 110. 2 shows an example of a system configuration of a module control unit 240. 1 shows an example of a system configuration of a system control unit 140. 2 shows an example of a circuit configuration of a power storage module 110. 2 shows an example of a circuit configuration of a module control unit 240. 10 shows an example of the circuit configuration of the discharge prevention circuit 720. 10 illustrates an example of the operation of the power storage system 100. 10A and 10B schematically illustrate an example of the operation and information processing of the power storage module 110. 10A and 10B schematically illustrate an example of the operation and information processing of the power storage module 110. 10A and 10B are schematic diagrams illustrating another example of the operation and information processing of the power storage module 110. 12 shows an example of a system configuration of a large-scale power system 1200. 12 illustrates an example of the operation of a large scale power system 1200. 3 shows an example of a system configuration of a computer 3000.

The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention as claimed. Not all combinations of features described in the embodiments are necessarily essential to the solution of the invention. Furthermore, the embodiments will be described with reference to the drawings. In describing the drawings, the same reference numbers may be used to designate identical or similar parts, and duplicate explanations may be omitted.

Furthermore, "electrically connected" does not necessarily mean that a specific element is directly connected to another element. A third element may be interposed between the specific element and the other element. Furthermore, it does not necessarily mean that the specific element is physically connected to the other element. For example, the input winding and output winding of a transformer are not physically connected, but are electrically connected. Furthermore, it includes not only cases where the specific element and the other element are actually electrically connected, but also cases where the specific element and the other element are electrically connected when the storage cell and the balance correction unit are electrically connected. Furthermore, "connected in series" means that the specific element and the other element are electrically connected in series, and "connected in parallel" means that the specific element and the other element are electrically connected in parallel.

(Outline of the power storage system 100)
1 schematically illustrates an example of a system configuration of a power storage system 100. In one embodiment, the power storage system 100 is electrically connected to a load device 12 and supplies power to the load device 12 (this may be referred to as discharging the power storage system 100). In another embodiment, the power storage system 100 is electrically connected to a charging device 14 and stores electric energy (this may be referred to as charging the power storage system 100). The power storage system 100 is used in, for example, a power storage device, an electrical appliance, a transportation device, etc. Examples of transportation devices include an electric vehicle, a hybrid vehicle, an electric motorcycle, a railroad vehicle, an airplane, an elevator, and a crane.

In this embodiment, the energy storage system 100 includes, for example, a connection terminal 102, a connection terminal 104, wiring 106, multiple energy storage modules 110, a charge/discharge control device 120, and a system control unit 140. Each of the multiple energy storage modules 110 has a positive terminal 112 and a negative terminal 114. In this embodiment, the energy storage system 100 includes, for example, multiple energy storage modules 110 connected in parallel.

In this embodiment, the connection terminal 102 and the connection terminal 104 electrically connect the energy storage system 100 to the load device 12 or the charging device 14. In this embodiment, the wiring 106 electrically connects the connection terminal 102 and the connection terminal 104. In this embodiment, one end of the wiring 106 is electrically connected to the connection terminal 102 via the charge/discharge control device 120. The other end of the wiring 106 is electrically connected to the connection terminal 104 via the charge/discharge control device 120. In this embodiment, the wiring 106 connects multiple energy storage modules 110 in parallel to the connection terminal 102 and the connection terminal 104.

In this embodiment, each of the multiple energy storage modules 110 is configured to be detachable from, for example, the wiring 106. This allows each of the multiple energy storage modules 110 to be detachably held in the housing of the energy storage system 100. In this embodiment, a user of the energy storage system 100 can individually replace each of the multiple energy storage modules 110.

In this embodiment, the energy storage module 110 exchanges power with the load device 12 or the charging device 14, which are located outside the energy storage system 100, via the charge/discharge control device 120. When the energy storage system 100 supplies power to the load device 12, the sum of the output power of each of the multiple energy storage modules 110 becomes the output power of the energy storage system 100. When the energy storage system 100 receives power from the charging device 14, the sum of the input power of each of the multiple energy storage modules 110 becomes the input power of the energy storage system 100.

In this embodiment, each of the multiple power storage modules 110 can switch the electrical connection state (sometimes simply referred to as the connection relationship) between the power storage unit (not shown) disposed in 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 multiple power storage modules 110 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.

As a result, even if the voltage of a new storage module 110 to be installed in the energy storage system 100 differs from the voltage of the storage modules 110 already installed in the energy storage system 100, the user of the energy storage system 100 can individually replace each of the multiple storage modules 110 included in the energy storage system 100 without worrying about damage or deterioration of the storage modules 110. The user of the energy storage system 100 can replace the storage modules 110, for example, by following the procedure below.

First, the user removes the old energy storage module 110 from the energy storage system 100. Next, before installing the new energy storage module 110 in the energy storage system 100, the user performs an operation to electrically disconnect the energy storage unit of the new energy storage module 110 from the wiring 106. For example, the user manually operates a switching element (not shown) arranged between the positive terminal 112 of the energy storage module 110 and the energy storage unit to electrically disconnect the positive terminal 112 from the energy storage unit.

The type of switching element is not particularly limited. The switching element may be a semiconductor switch, a contactor, or a relay.

The user then installs the storage module 110, with the positive terminal 112 and the storage unit electrically disconnected, into the storage system 100. At this time, the positive terminal 112 and the storage unit are electrically disconnected. Therefore, even if there is a relatively large voltage difference between the storage module 110 newly installed in the storage system 100 and the storage system 100 already installed in the storage system 100, a large current is prevented from flowing between the newly installed storage module 110 and the storage system 100 already installed.

After that, when the voltage difference between the newly installed energy storage module 110 and the already installed energy storage system 100 reaches an appropriate value, the system control unit 140 performs an operation to electrically connect the newly installed energy storage module 110 to the wiring 106. Details of the system control unit 140 will be described later.

As described above, with the energy storage system 100 according to this embodiment, when a user of the energy storage system 100 replaces or installs an energy storage module 110, there is no need to precisely adjust the voltage of the energy storage module 110 newly installed in the energy storage system 100 and the voltage of the energy storage module 110 already installed in the energy storage system 100. This allows the user of the energy storage system 100 to easily and quickly replace or install a storage module 110.

(Discharge prevention control)
In this embodiment, when it is predicted that the switching element described above will switch from an on state to an off state (sometimes referred to as an off operation), the power storage module 110 outputs a signal (sometimes referred to as a warning signal) to the system control unit 140 to warn that the switching element will be turned off. After outputting the warning signal, the power storage module 110 determines whether or not a condition (sometimes referred to as a disconnection permission condition) for permitting the off operation of the switching element is met. If the disconnection permission condition is met, the power storage module 110 turns off the switching element.

The disconnection permission conditions may be conditions for suppressing damage to the switching element due to arc discharge, or conditions for preventing the occurrence of arc discharge. Details of the disconnection permission conditions will be described later.

In this embodiment, the charge/discharge control device 120 controls at least one of the input power and the output power of the power storage system 100. The charge/discharge control device 120 controls at least one of the input power and the output power of the power storage system 100, for example, in accordance with a control signal from the system control unit 140.

This allows the charge/discharge control device 120 to control the charging/discharging of at least one of the multiple storage modules 110. The magnitude of the current flowing through the storage module 110 can also be adjusted. As described above, the storage module 110 includes, for example, a storage unit and a switching element. Therefore, by the charge/discharge control device 120 controlling at least one of the input power and output power of the storage system 100, the magnitude of the current flowing through the storage unit and/or switching element arranged in the storage module 110 can be adjusted, for example.

In one embodiment, the charge/discharge control device 120 adjusts the magnitude of at least one of the voltage and current of the input power to the power storage system 100. The charge/discharge control device 120 may stop the input of power to the power storage system 100. In another embodiment, the charge/discharge control device 120 adjusts the magnitude of at least one of the voltage and current of the output power from the power storage system 100. The charge/discharge control device 120 may stop the output of power from the power storage system 100.

In yet another embodiment, the charge/discharge control device 120 may convert AC power input to the energy storage system 100 into DC power. This DC power is then supplied to the energy storage module 110. Also, the charge/discharge control device 120 may convert DC power output by the energy storage module 110 into AC power. This AC power is then supplied to the load device 12.

The charge/discharge control device 120 may include a power terminal (not shown) electrically connected to the connection terminal 102, a power terminal (not shown) electrically connected to the connection terminal 104, a power terminal (not shown) electrically connected to one end of the wiring 106, and a power terminal (not shown) electrically connected to the other end of the wiring 106.

The charge/discharge control device 120 is preferably a device that can adjust the magnitude of at least one of the voltage and current of the input power and/or output power of the power storage system 100 without generating an arc discharge large enough to damage the barrier that constitutes the charge/discharge control device 120. Examples of the charge/discharge control device 120 include a DC/DC converter, a DC/AC inverter, and an on/off switch. The DC/DC converter may be a unidirectional DC/DC converter or a bidirectional DC/DC converter. The DC/AC inverter may be a unidirectional DC/AC inverter or a bidirectional DC/AC inverter.

The charge/discharge control device 120 is preferably a DC/DC converter or a DC/AC inverter. When the charge/discharge control device 120 is a DC/DC converter or a DC/AC inverter, when the charge/discharge control device 120 adjusts the magnitude of at least one of the voltage and current of the input power and/or output power of the energy storage system 100, the occurrence of arc discharge that could damage the barriers that make up the charge/discharge control device 120 is prevented.

In this embodiment, the system control unit 140 controls each unit of the energy storage system 100. For example, the system control unit 140 controls the operation of the energy storage module 110. For example, the system control unit 140 controls the operation of the charge/discharge control device 120. Details of the above control will be described later.

In this embodiment, the system control unit 140 may manage the state of each unit of the power storage system 100. 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. In another embodiment, the system control unit 140 monitors the state of the charge/discharge control device 120. For example, the system control unit 140 monitors the magnitude of at least one of the voltage and current of the input power input to the charge/discharge control device 120 from the load device 12 or the charging device 14. For example, the system control unit 140 monitors the magnitude of at least one of the voltage and current of the output power output from the charge/discharge control device 120 to the load device 12.

In yet another embodiment, the system control unit 140 monitors the status of each of the multiple storage modules 110. For example, the system control unit 140 collects information regarding the battery characteristics of the storage units included in each of the multiple storage modules 110.

Examples of information related to the battery characteristics of the power storage unit include at least one selected from the voltage value of the power storage unit, the value of the current flowing through the power storage unit, the battery capacity of the power storage unit, the temperature of the power storage unit, the deterioration state of the power storage unit, and the SOC (State of Charge) of the power storage unit. Information related to the battery characteristics of the power storage unit (sometimes referred to as the battery characteristics of the power storage module 110. The battery characteristics of the power storage unit may be the battery characteristics of a single cell among the multiple cells that make up the power storage module 110, or the battery characteristics of a combination of the multiple cells) may include at least one of information related to the specifications of the power storage unit and information related to the deterioration state of the power storage unit.

Examples of information related to the specifications of the storage unit include the type or model of the storage unit, the connection state of the storage unit, the type of charging method that can charge the storage unit, the type of charging method that cannot charge the storage unit, the rated battery capacity (sometimes referred to as rated capacity), the rated voltage, the rated current, the energy density, the maximum charge/discharge current, the charge characteristics, the charge temperature characteristics, the discharge characteristics, the discharge 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, and the storage voltage [V]. Examples of charging methods include the CCCV method, the CC method, and the trickle charging method.

Examples of the connection state of the power storage unit include the type of unit cells constituting the power storage unit, the number of 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, the number of unit cells connected in parallel, etc. The energy density may be a volumetric energy density [Wh/m ³ ] or a weight energy density [Wh/kg].

Examples of information related to the degradation state of the power storage unit include information related to the power storage unit at any point in time, such as (i) battery capacity in a fully charged state, (ii) SOC [%] under predetermined temperature conditions, (iii) SOH (State of Health), (iv) equivalent series resistance (DCR, sometimes referred to as internal resistance), and (v) accumulated usage time from the initial state or a predetermined timing, number of charges, charge amount, discharge amount, number of charge/discharge cycles, temperature stress factor, and/or overcurrent stress factor. Information related to the battery characteristics of the power storage unit may be information that associates information related to the degradation state of the power storage unit with information related to the time at which the information was acquired. Information related to the battery characteristics of the power storage unit may store information related to the degradation state of the power storage unit at multiple times.

The system control unit 140 may transmit information regarding the battery characteristics of the power storage unit included in the power storage module 110 to an external device. This allows the external device to use the information regarding the battery characteristics of the power storage unit. Examples of external devices include the load device 12 and the charging device 14. The external device may also be an output device that outputs information to the user. Examples of output devices include a display device such as a monitor, or an audio output device such as a microphone.

(Connection Control)
In this embodiment, the system control unit 140 determines the order in which the multiple power storage modules 110 are electrically connected to the wiring 106 based on the voltage of the power storage unit of each of the multiple power storage modules 110. The system control unit 140 may also determine the order in which the multiple power storage modules 110 are electrically connected to the wiring 106 based on the voltage between the terminals of each of the multiple power storage modules 110.

For example, when starting operation of the power storage system 100, if the power storage system 100 starts in a charging state, the system control unit 140 electrically connects the power storage unit of the power storage module 110 with the lowest voltage among the multiple power storage modules 110 to the wiring 106. On the other hand, when starting operation of the power storage system 100, if the power storage system 100 starts in a discharging state, the system control unit 140 electrically connects the power storage unit of the power storage module 110 with the highest voltage among the multiple power storage modules 110 to the wiring 106.

In one embodiment, the system control unit 140 may transmit a signal to each of the multiple storage modules 110 to connect the power storage unit to the wiring 106 in the order determined as described above. In another embodiment, the system control unit 140 may select the storage module 110 with the lowest voltage or SOC, or the storage module 110 with the highest voltage or SOC, and transmit a signal to connect the power storage unit to the wiring 106 only to the selected storage module.

(Discharge prevention control)
In the present embodiment, when it is predicted that a switching element arranged in at least one of the multiple power storage modules 110 will switch from an ON state to an OFF state (sometimes referred to as an OFF operation), the system control unit 140 reduces the magnitude of the input current or output current of the power storage system 100 before the switching element performs the OFF operation. For example, when it is predicted that at least one of the multiple power storage modules 110 or any one of the multiple power storage modules 110 will be fully charged or fully discharged, the system control unit 140 reduces the magnitude of the input current or output current of the power storage system 100 in advance. When the system control unit 140 receives a warning signal from at least one of the multiple power storage modules 110 or any one of the multiple power storage modules 110, the system control unit 140 may reduce the magnitude of the input current or output current of the power storage system 100 in advance.

The system control unit 140 may control the operation of the charge/discharge control device 120 to reduce the magnitude of the input current or output current of the power storage system 100. In one embodiment, the system control unit 140 reduces the magnitude of the input current or output current of the power storage system 100 to 1/2 or less of the rated current of the switching element. The system control unit 140 may also reduce the magnitude of the input current or output current of the power storage system 100 to 1/4 or less of the rated current of the switching element. In another embodiment, the system control unit 140 may reduce the magnitude of the input current or output current of the power storage system 100 to substantially zero.

As mentioned above, when a switching element switches from an on state to an off state while a current is flowing through the switching element, arc discharge may occur inside the switching element. For example, when the terminal voltage of the energy storage module 110 reaches 100 V or higher, arc discharge is likely to occur. When the terminal voltage of the energy storage module 110 reaches a high voltage of 750 V or higher, arc discharge is particularly likely to occur.

For example, if the magnitude of the current flowing through a switching element is halved, the amount of energy released by arc discharge will be 1/4. Therefore, by reducing the magnitude of the current flowing through the switching element before the switching element is turned off, damage to the switching element caused by arc discharge can be suppressed. Furthermore, if the magnitude of the current flowing through the switching element is sufficiently small, the occurrence of arc discharge itself can be prevented.

As described above, arc discharge is likely to occur when the terminal voltage of the storage module 110 is 100V or higher. Therefore, the above control is particularly effective when the terminal voltage of the storage module 110 exceeds 100V. In addition, the above control is extremely effective when the terminal voltage of the storage module 110 is 750V or higher, when the terminal voltage of the storage module 110 exceeds 750V, when the terminal voltage of the storage module 110 is 1000V or higher, when the terminal voltage of the storage module 110 exceeds 1000V, when the terminal voltage of the storage module 110 is 1500V or higher, or when the terminal voltage of the storage module 110 exceeds 1500V. The above control can also be sufficiently effective when the terminal voltage of the storage module 110 is less than 100V.

In order to prevent damage to switching elements due to arc discharge, SiC can be used, for example, as a material for switching elements. However, in high-voltage applications such as those described above, even if SiC is used as the switching element material, it is difficult to prevent damage to the switching element. Furthermore, the cost of the switching element is very high. In contrast, according to this embodiment, the occurrence of arc discharge is prevented and the energy released by arc discharge is greatly reduced. This prevents the specifications required for the switching element from becoming too advanced. As a result, for example, relatively inexpensive general-purpose products can be used as the above switching elements. Furthermore, even when expensive switching elements are used, damage to the elements can be prevented.

(Example of a specific configuration of the system control unit 140)
The system control unit 140 may be realized by hardware or software. Alternatively, it may 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, ROM, RAM, a communication interface, etc.

A program installed on a computer that causes the computer to function as 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 the CPU or the like to cause the computer to function as each part of the system control unit 140.

When the information processing described in these programs is loaded into a computer, it functions as specific means in which the software and the various hardware resources described above work together. These specific means allow the computer in this embodiment to perform calculations or processing of information according to its intended use, thereby constructing a unique device according to its intended use. The programs may be stored on computer-readable media or on a storage device connected to a network.

An example of the above information processing is a control method for an adjustment device that adjusts the magnitude of current. The above control method, for example, includes a third signal output step in which, when a first signal is received to notify that the power storage device and the adjustment device that adjusts the magnitude of the current flowing through the power storage device will be electrically disconnected, a third signal is output to the adjustment device to reduce the magnitude of the current flowing through the power storage device below a predetermined second threshold. Each step of the above information processing may be performed by a computer.

The load device 12 may be an example of an external device. The charging device 14 may be an example of an external device. The power storage system 100 may be an example of a power transfer system. The power storage module 110 may be an example of a power storage device. A power storage device may be an example of a power transfer device. Some of the multiple power storage modules 110 may be an example of a power storage device. Other parts of the multiple power storage modules 110 may be examples of other power transfer devices. The positive terminal 112 may be an example of a power terminal of a power storage device. The negative terminal 114 may be an example of a power terminal of a power storage device. The charge/discharge control device 120 may be an example of an adjustment device. The system control unit 140 may be an example of a current control device or a third signal output unit.

(An example of another embodiment)
In the present embodiment, an example of the power storage system 100 has been described, taking as an example a case where a user performs an operation to electrically disconnect the power storage unit of a new power storage module 110 from the wiring 106 before the new power storage module 110 is installed in the power storage system 100. However, 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 to start 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.

In this embodiment, an example of the power storage system 100 has been described using the power storage module 110 as an example of a power transfer device configured to be able to transfer power. However, the power storage system 100 is not limited to this embodiment. In other embodiments, the power transfer device may be a power supply device configured to be able to supply power. Examples of power supply devices include a primary battery, a fuel cell, and a power generation device.

In this embodiment, an example of the power storage system 100 has been described, taking as an example a case where, when the system control unit 140 receives a warning signal, the system control unit 140 controls the operation of the charge/discharge control device 120 to preliminarily reduce the magnitude of the input current or output current of the power storage system 100. However, the power storage system 100 is not limited to this embodiment. In other embodiments, when the system control unit 140 receives a warning signal, the system control unit 140 may control the operation of the charging device 14 to preliminarily reduce the magnitude of the input current or output current of the power storage system 100.

Figure 2 shows a schematic diagram of an example of the system configuration of the power storage module 110. In this embodiment, the power storage module 110 includes a power storage unit 210 having a positive terminal 212 and a negative terminal 214, a switching unit 230, a module control unit 240, a protection unit 250, and a balance correction unit 260. Furthermore, in this embodiment, the power storage unit 210 includes a power storage cell 222 and a power storage cell 224.

The switching element described in relation to FIG. 1 may be an example of the switching unit 230. The power storage unit described in relation to FIG. 1 may be an example of the power storage unit 210.

In this embodiment, the power storage unit 210 is configured to be chargeable and dischargeable. The impedance of the power storage unit 210 may be 1 Ω or less, or 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.

With the energy storage system 100 according to this embodiment, for example, when replacing one of a plurality of energy storage modules 110 connected in parallel, it is not necessary to precisely match the voltage of the energy storage module 110 being newly added to the energy storage system 100 with the voltages of the remaining energy storage modules 110. Therefore, even if the impedance of the energy storage unit 210 is small, the energy storage module 110 can be easily and quickly replaced.

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 be a lithium-ion battery. At least one of the power storage cell 222 and the power storage cell 224 may further include multiple power storage cells connected in series, parallel, or in a matrix within the power storage cell.

In this embodiment, the switching unit 230 is disposed between the positive terminal 112 and the power storage unit 210. As a result, 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 state between the positive terminal 112 and the power storage unit 210. The switching unit 230 may switch the electrical connection state between the positive terminal 112 and the power storage unit 210 based on a signal (sometimes referred to as a switching control signal) generated by the module control unit 240.

Specifically, the switching unit 230 switches between a state in which the positive terminal 112 and the power storage unit 210 are electrically connected (sometimes referred to as an ON state), and a state in which the positive terminal 112 and the power storage unit 210 are electrically disconnected (sometimes referred to as an OFF state). This also switches the electrical connection state between the wiring 106 and the power storage unit 210.

As described above, when the energy storage module 110 is installed in the energy storage system 100, the energy storage module 110 may be installed in the energy storage system 100 with the switching unit 230 electrically disconnecting the energy storage unit 210 from the wiring 106. This can prevent damage or deterioration of the energy storage module 110.

The switching unit 230 may be implemented using hardware, software, or a combination of hardware and software. The switching unit 230 may be implemented using an analog circuit, a digital circuit, or a combination of an analog circuit and a digital circuit. 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 arranged between the positive terminal 112 and the positive terminal 212, or between the negative terminal 114 and the negative terminal 214.

Examples of switching elements include contactors, relays, thyristors, and transistors. The thyristors may be bidirectional thyristors (sometimes called triacs). The transistors may be semiconductor transistors. The semiconductor transistors may be bipolar transistors or field-effect transistors. The field-effect transistors may be MOSFETs. When the terminal voltage of the energy storage module 110 is 750 V or higher, the switching elements are preferably contactors, relays, or SiC power semiconductor elements.

In this embodiment, the module control unit 240 controls the current flowing between the power storage unit 210 of the power storage module 110 and the wiring 106. The module control unit 240 may also control the operation of the switching unit 230.

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 112 and the positive terminal 212) satisfies a predetermined condition (sometimes referred to as a connection permission 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 112.

On the other hand, if the terminal voltage of the switching unit 230 does not satisfy the predetermined condition, the module control unit 240 controls the switching unit 230 so that the switching unit 230 electrically disconnects the power storage unit 210 from the wiring 106 or the positive terminal 112. The switching unit 230 may electrically disconnect the power storage unit 210 from the wiring 106 by electrically disconnecting the power storage unit 210 from the positive terminal 112.

The connection permission condition may be (i) a condition that the terminal voltage of the switching unit 230 meets a condition under which electrical connection between the power storage unit 210 and the wiring 106 is permitted, or (ii) a condition that the terminal voltage of the switching unit 230 does not meet a condition under which electrical connection between the power storage unit 210 and the wiring 106 is prohibited. The connection permission condition may be a condition under which the absolute value of the terminal voltage of the switching unit 230 is within a predetermined numerical range (sometimes referred to as the connection permission range).

The connection allowable range may be 3V or less, 1V or less, 0.1V or less, 10mV or less, or 1mV or less. The connection allowable range may also be 0.5mV or more, or 1mV or more. The connection allowable range may also be 0.5mV or more and 0.5mV or more and 3V or less. The connection allowable range may also 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 more and 0.1V or more and 1V or less. The inter-terminal voltage of the switching unit 230 may be the voltage between the positive terminal 112 and the positive terminal 212, or the voltage between the wiring 106 and the power storage unit 210.

The permitted connection range may be set based on the impedance of the power storage unit 210. The permitted connection range may be set based on the rated current or allowable current of the power storage unit 210. The permitted connection 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 permitted connection range may be set based on the rated current or allowable current of the element that has the smallest rated current or allowable current among the elements that make up the power storage module 110. The permitted connection range may be set based on the impedance of the power storage module 110 and the rated current or allowable current of the element that has the smallest rated current or allowable current among the elements that make up the power storage module 110.

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

In this embodiment, the module control unit 240 receives a signal (sometimes referred to as a minimum notification signal) from the system control unit 140 indicating that the terminal voltage of the power storage module 110 is lower than the terminal voltages of the other power storage modules. When the module control unit 240 receives this signal when the power storage system 100 transitions to a charging state, it controls the switching unit 230 so that the switching unit 230 electrically connects the power storage unit 210 and the wiring 106. This allows multiple power storage modules 110 connected in parallel to be efficiently charged.

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

In this embodiment, the module control unit 240 receives a signal (sometimes referred to as a disconnection control signal) from the system control unit 140 indicating whether the switching unit 230 can be turned off. Examples of disconnection control signals include a signal indicating that the switching unit 230 is prohibited from turning off, a signal indicating that the switching unit 230 is not prohibited from turning off, and a signal indicating that the switching unit 230 is permitted to turn off.

In this embodiment, the module control unit 240 outputs the above-mentioned warning signal to the system control unit 140 when it is predicted that the switching unit 230 will be turned off. After outputting the warning signal, the module control unit 240 determines whether the above-mentioned disconnection permission condition is met. If the disconnection permission condition is met, the energy storage module 110 turns off the switching unit 230.

Examples of disconnection permission conditions include at least one of the following: (i) a predetermined time has elapsed after the module control unit 240 output a warning signal; (ii) a process has been executed to reduce the magnitude of the current flowing through the switching unit 230 to less than a predetermined value (sometimes referred to as the second threshold) after the module control unit 240 output a warning signal; (iii) the module control unit 240 outputs a warning signal and the magnitude of the current flowing through the switching unit 230 is less than the second threshold; and (iv) the module control unit 240 outputs a warning signal and the switching unit 230 is not prohibited from turning off or is permitted to turn off. Whether the switching unit 230 is prohibited from turning off is determined, for example, based on the disconnection control signal described above.

If the module control unit 240 receives a disconnection control signal indicating that the switching unit 230 is prohibited from turning off, the module control unit 240 may determine that the switching unit 230 is prohibited from turning off. If the module control unit 240 receives a disconnection control signal indicating that the switching unit 230 is not prohibited from turning off, or a disconnection control signal indicating that the switching unit 230 is permitted to turn off, or if the module control unit 240 does not receive a disconnection control signal indicating that the switching unit 230 is prohibited from turning off, the module control unit 240 may determine that the switching unit 230 is not prohibited from turning off, or that the switching unit 230 is permitted to turn off.

In this embodiment, the module control unit 240 receives a signal from the protection unit 250 indicating that the terminal voltage of the storage cell 222 or the storage cell 224 is not within a predetermined range. In one embodiment, if the terminal voltage of the storage cell 222 or the storage cell 224 exceeds a reference value for overvoltage, the module control unit 240 receives a signal indicating overvoltage (sometimes referred to as an OVP signal) from the protection unit 250. In another embodiment, if the terminal voltage of the storage cell 222 or the storage cell 224 exceeds a reference value for overdischarge, the module control unit 240 receives a signal indicating overdischarge (sometimes referred to as a UVP signal) from the protection unit 250.

When the module control unit 240 receives these signals, it 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 prevent deterioration or damage to the power storage unit 210 due to overcharging or over-discharging.

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

In this embodiment, the module control unit 240 may acquire information regarding the battery characteristics of the power storage unit 210. The module control unit 240 may output the information regarding the battery characteristics of the power storage unit 210 to an external device. This allows the external device to use the information regarding the battery characteristics of the power storage unit 210. Examples of external devices include the load device 12 and the charging device 14. The external device may also be an output device that outputs information to a user.

(Example of a specific configuration of the module control unit 240)
The module control unit 240 may be realized by hardware or software. Alternatively, 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, ROM, RAM, a communication interface, etc.

A program installed on a computer that causes the computer to function as 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 the CPU or the like to cause the computer to function as each part of the module control unit 240.

When the information processing described in these programs is loaded into a computer, it functions as specific means in which the software and the various hardware resources described above work together. These specific means enable the computer in this embodiment to perform calculations or processing of information according to its intended use, thereby enabling the construction of a unique device according to its intended use. The programs may be stored on computer-readable media, or on a storage device connected to a network. The computer-readable media may be non-transitory computer-readable media.

The above information processing may be a control method for a switching device. The above switching device, for example, switches the electrical connection state between an electric storage device of an electric storage device and a power terminal of the electric storage device. The above control method, for example, includes a first determination step of determining whether the voltage of the electric storage device has reached a predetermined first threshold. The above control method, for example, includes a first signal output step of outputting a first signal to notify the electric storage device and the power terminal that they will be electrically disconnected when it is determined that the voltage of the electric storage device has reached the first threshold. The above control method, for example, includes a second signal output step of outputting a second signal to the switching device to electrically disconnect the electric storage device and the power terminal when a disconnection permission condition, which is a condition for permitting the electric disconnection of the electric storage device and the power terminal, is met after the first signal is output in the first signal output step. Each step of the above information processing may be performed by a computer.

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 over-discharging. 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, it transmits a signal indicating this to the module control unit 240. The protection unit 250 may transmit information regarding the terminal voltage of the power storage unit 210 (sometimes referred to as voltage information) to the system control unit 140.

The protection unit 250 may be implemented using hardware, software, or a combination of hardware and software. The protection unit 250 may be implemented using analog circuits, digital circuits, or a combination of analog and digital circuits.

The balance correction unit 260 equalizes the voltages of multiple storage cells. The operating principle of the balance correction unit 260 is not particularly limited, and any balance correction device can be used. If 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, if the power storage unit 210 has n storage cells (n is an integer greater than or equal to 2), the power storage module 110 has n-1 active balance correction units 260 or n passive balance correction units 260.

The balance correction unit 260 may be implemented using hardware, software, or a combination of hardware and software. The balance correction unit 260 may be implemented using 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 balance correction device. An active 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 Laid-Open No. 2006-067742, or a balance correction unit that transfers charge using a capacitor, as described in Japanese Patent Application Laid-Open No. 2012-210109. In another embodiment, the balance correction unit 260 may be a passive balance correction device. A passive balance correction device, for example, uses an external resistor to release excess charge.

In this embodiment, the power storage unit 210 has been described as having two storage cells connected in series. 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 multiple storage cells connected in parallel, or multiple cells connected in a matrix.

The power storage unit 210 may be an example of a power storage unit or a power storage device. The switching unit 230 may be an example of a switching device. The module control unit 240 may be an example of a switching control device. The turning-off operation of the switching unit 230 may be an example of electrically disconnecting the power storage unit and the power terminal. The warning signal may be an example of a first signal.

(An example of another embodiment)
In the present embodiment, the positive electrode terminal 212 of the power storage unit 210 of the power storage module 110 is electrically connected to the wiring 106 of the power storage system 100 via the switching unit 230 and the positive electrode terminal 112 of the power storage module 110. Furthermore, the negative electrode terminal 214 of the power storage unit 210 of the power storage module 110 is electrically connected to the wiring 106 of the power storage system 100 via the negative electrode terminal 114 of the power storage module 110. However, the power storage module 110 is not limited to this embodiment. In other embodiments, the negative electrode terminal 214 of the power storage unit 210 is electrically connected to the wiring 106 of the power storage system 100 via the switching unit 230 and the negative electrode terminal 114 of the power storage module 110. Furthermore, the positive electrode terminal 212 of the power storage unit 210 is electrically connected to the wiring 106 of the power storage system 100 via the positive electrode terminal 112 of the power storage module 110.

In this embodiment, an example of the storage module 110 has been described, taking as an example a case where the protection unit 250 transmits an OVP signal and a UVP signal to the module control unit 240 at the positive terminal 212 of the storage unit 210. However, the storage module 110 is not limited to this embodiment. In other embodiments, the protection unit 250 may output at least one of the OVP signal and the UVP signal to the switching unit 230. The protection unit 250 may output at least one of the OVP signal and the UVP signal to the system control unit 140.

In this embodiment, an example of the power storage system 100 has been described, taking as an example a case in which the system control unit 140 performs an operation to electrically connect the power storage unit 210 of a power storage module 110 newly installed in the power storage system 100 to the wiring 106 of the power storage system 100. However, the power storage system 100 is not limited to this embodiment.

In other embodiments, the module control unit 240 of a storage module 110 constituting the power storage system 100, or of a storage module 110 newly installed in the power storage system 100, may have some of the functions of the system control unit 140. For example, the module control unit 240 of a storage module 110 newly installed in the power storage system 100 performs an operation to electrically connect the power storage unit 210 of the storage module 110 to the wiring 106 of the power storage system 100. Similarly, the system control unit 140 may have some of the functions of the module control unit 240 described in relation to this embodiment.

Figure 3 shows an example of the system configuration of the module control unit 240. In this embodiment, the module control unit 240 includes a connection determination unit 310, a receiving unit 320, and a signal generation unit 330. The module control unit 240 may also include a module information acquisition unit 340, a module information storage unit 350, and a module information transmission unit 360.

In this embodiment, the connection determination unit 310 determines whether the voltage between the terminals of the switching unit 230 is within the connection permission range. The connection determination unit 310 transmits a signal indicating the determination result to the signal generation unit 330. The connection determination unit 310 may be any comparator or comparison circuit. The connection determination unit 310 may also be a window comparator.

In this embodiment, the charge state determination unit 312 determines whether the voltage of the power storage unit 210 has reached a predetermined value (sometimes referred to as the first threshold). The first threshold may be (i) a value obtained by subtracting a predetermined value from the full charge voltage of the power storage unit 210, or (ii) a value obtained by adding a predetermined value to the end-of-discharge voltage of the power storage unit 210.

If the first threshold is the full charge voltage of the power storage unit 210 minus a predetermined value, the charge state determination unit 312 determines that the voltage of the power storage unit 210 has reached the first threshold, for example, when the current voltage of the power storage unit 210 changes from a value smaller than the first threshold to equal the first threshold, or when the current voltage of the power storage unit 210 changes from a value smaller than the first threshold to a value larger than the first threshold. If the first threshold is the discharge end voltage of the power storage unit 210 plus a predetermined value, the charge state determination unit 312 determines that the voltage of the power storage unit 210 has reached the first threshold, for example, when the current voltage of the power storage unit 210 changes from a value larger than the first threshold to equal the first threshold, or when the current voltage of the power storage unit 210 changes from a value larger than the first threshold to a value smaller than the first threshold.

As described above, in this embodiment, the power storage unit 210 has multiple storage cells connected in series. The charge state determination unit 312 may determine that the voltage of the power storage unit 210 has reached the first threshold when the voltage of at least one of the multiple storage cells reaches the first threshold. In this case, the first threshold may be (i) a value obtained by subtracting a predetermined value from the full charge voltage of the storage cell, or (ii) a value obtained by adding a predetermined value to the end-of-discharge voltage of the storage cell. Whether the voltage of the storage cell included in the power storage unit 210 has reached the first threshold may be determined using a procedure similar to the procedure for determining whether the voltage of the power storage unit 210 has reached the first threshold, described above.

The charging state determination unit 312 transmits a signal indicating the determination result to the signal generation unit 330. The charging state determination unit 312 may be any comparator or comparison circuit. The charging state determination unit 312 may also be a window comparator. The charging state determination unit 312 may have multiple window comparators. For example, the charging state determination unit 312 has a window comparator for determining full charge and a window comparator for determining the end of discharge.

In this embodiment, the disconnection determination unit 314 determines whether the above-described disconnection permission conditions are met. The charging state determination unit 312 sends a signal indicating the determination result to the signal generation unit 330.

For example, the disconnection determination unit 314 obtains information indicating the determination result from the charging state determination unit 312. The disconnection determination unit 314 may determine whether or not a warning signal is to be output based on the determination result of the charging state determination unit 312. The disconnection determination unit 314 may obtain information indicating that a warning signal has been output or information indicating the time when the warning signal was output from the signal generation unit 330. The disconnection determination unit 314 may obtain information indicating the current value of the current flowing through the power storage unit 210 and the switching unit 230 from the protection unit 250. The disconnection determination unit 314 may obtain a disconnection control signal from the system control unit 140. The disconnection determination unit 314 determines whether or not the above-mentioned disconnection permission condition is met, for example, based on at least one of these pieces of information.

In this embodiment, the receiving unit 320 receives at least one of a signal from the system control unit 140, a signal from the protection unit 250, and an instruction from the user. The receiving unit 320 outputs a signal corresponding to the received information to at least one of the disconnection determination unit 314 and the signal generation unit 330.

In this embodiment, the signal generation unit 330 acquires various information from at least one of the connection determination unit 310, the receiving unit 320, the charging state determination unit 312, and the disconnection determination unit 314. In one embodiment, the signal generation unit 330 generates a switching control signal for controlling the switching unit 230 based on this information. The signal generation unit 330 outputs the generated switching control signal to the switching unit 230. In another embodiment, the signal generation unit 330 generates a warning signal based on this information. The signal generation unit 330 outputs the generated warning signal to the system control unit 140.

(Hot Insertion/Removal Control)
In one embodiment, when the connection determination unit 310 determines that the voltage between the terminals of the switching unit 230 is within the connection permission range, the signal generation unit 330 generates a signal for turning on the switching element of the switching unit 230. In another embodiment, when the connection determination unit 310 determines that the voltage between the terminals of the switching unit 230 is not within the connection permission range, the signal generation unit 330 generates a signal for turning off the switching element of the switching unit 230.

The signal generating unit 330 may generate or transmit a signal a predetermined time after the connection determining unit 310 determines whether the terminal voltage of the switching unit 230 is within the connection permission range. This can prevent malfunctions due to noise, etc. Furthermore, it can prevent the power storage unit 210 and the wiring 106 from being electrically connected immediately after the power storage module 110 is attached to the power storage system 100.

(Switching control)
In this embodiment, the signal generating unit 330 generates a signal for controlling the switching element of the switching unit 230 based on the signal received by the receiving unit 320. In one embodiment, when the receiving unit 320 receives a signal for turning on the switching element of the switching unit 230 from the system control unit 140, the signal generating unit 330 generates a signal for turning on the switching element of the switching unit 230.

In another embodiment, when the receiving unit 320 receives a signal from the protection unit 250 to turn off the switching element of the switching unit 230, the signal generating unit 330 generates a signal to turn off the switching element of the switching unit 230. In yet another embodiment, when the receiving unit 320 receives a user instruction, the signal generating unit 330 generates a signal to operate the switching element of the switching unit 230 in accordance with the user instruction.

(Discharge prevention control)
In this embodiment, the signal generating unit 330 generates a warning signal based on the determination result of the charge state determining unit 312. For example, when it is determined that the voltage of the power storage unit 210 has reached the first threshold, the signal generating unit 330 generates the warning signal. The signal generating unit 330 may output the generated warning signal to the system control unit 140.

In this embodiment, the signal generating unit 330 generates a switching control signal for turning off the switching unit 230 based on the determination result of the disconnection determination unit 314. For example, if the disconnection permission condition is met after the signal generating unit 330 outputs the warning signal, the signal generating unit 330 generates a switching control signal for turning off the switching unit 230. The signal generating unit 330 may output the generated switching control signal to the switching unit 230.

In this embodiment, the module information acquisition unit 340 acquires information regarding the battery characteristics of the power storage unit 210. The module information acquisition unit 340 may acquire information regarding the battery characteristics of the power storage unit 210 by measuring the battery characteristics of the power storage unit 210. The module information acquisition unit 340 may acquire information regarding the battery characteristics of the power storage unit 210 input by a manufacturer, seller, etc. at the time of shipment, inspection, or sale.

The module information acquisition unit 340 may store information relating to the battery characteristics of the power storage unit 210 in the module information storage unit 350. The specific configuration of the module information acquisition unit 340 is not particularly limited, but the module information acquisition unit 340 may be a controller that controls the reading and writing of data in the module information storage unit 350. In this embodiment, the module information storage unit 350 stores information relating to the battery characteristics of the power storage unit 210 acquired by the module information acquisition unit 340.

In this embodiment, the module information transmission unit 360 transmits information regarding the battery characteristics of the power storage unit 210 acquired by the module information acquisition unit 340 to the system control unit 140. The module information transmission unit 360 may transmit the information regarding the battery characteristics of the power storage unit 210 acquired by the module information acquisition unit 340 to an external device. The module information transmission unit 360 may transmit the information regarding the battery characteristics of the power storage unit 210 in response to a request from the external device, or may transmit the information regarding the battery characteristics of the power storage unit 210 at a predetermined timing. The module information transmission unit 360 may refer to the module information storage unit 350 and transmit the information regarding the battery characteristics of the power storage unit 210 to the system control unit 140 or an external device.

The charging state determination unit 312 may be an example of a first determination unit. The signal generation unit 330 may be an example of a first signal output unit or a second signal output unit. The switching control signal for turning off the switching unit 230 may be an example of a second signal.

Figure 4 shows an example of the system configuration of the system control unit 140. In this embodiment, the system control unit 140 includes a status management unit 410, a module selection unit 420, an output fluctuation determination unit 422, and a signal generation unit 430.

In this embodiment, the state management unit 410 manages the state of the energy storage system 100. The state management unit 410 may manage the state of each of the multiple energy storage modules 110. The state management unit 410 may monitor the state of each of the multiple energy storage modules 110. The state management unit 410 may monitor each of the multiple energy storage modules 110 and obtain information regarding the battery characteristics of each of the multiple energy storage modules 110. The state management unit 410 may transmit the information obtained by monitoring each of the multiple energy storage modules 110 to an external device.

The status management unit 410 may measure the battery characteristics of each storage module while operating the energy storage system 100. If the battery characteristics of a storage module do not satisfy predetermined conditions, the status management unit 410 may output information indicating that the performance of the storage module is insufficient to an output device that outputs information to the user. The status management unit 410 may output the identification information of the storage module and information indicating that the performance of the storage module is insufficient.

This allows the user to easily identify storage modules with insufficient performance and replace them. According to this embodiment, for example, when constructing a storage system 100 using reused storage modules, it is possible to omit at least some of the inspection of the reused storage modules.

In one embodiment, when the energy storage system 100 transitions to a charging state, the module selection unit 420 selects the energy storage module 110 with the smallest terminal voltage from among the multiple energy storage modules 110 included in the energy storage system 100. The module selection unit 420 transmits a signal indicating the selected energy storage module 110 to the signal generation unit 430.

In another embodiment, when the energy storage system 100 transitions to a discharging state, the module selection unit 420 selects the energy storage module 110 with the highest terminal voltage from among the multiple energy storage modules 110 included in the energy storage system 100. The module selection unit 420 transmits a signal indicating the selected energy storage module 110 to the signal generation unit 430.

In this embodiment, the output fluctuation determination unit 422 determines whether or not it is acceptable to fluctuate the output of the power storage system 100. The signal generation unit 430 may perform the above determination process when it receives a warning signal, or may perform the above determination process regardless of the warning signal. The output fluctuation determination unit 422 determines whether or not it is acceptable to fluctuate the output of the power storage system 100 based on, for example, the state of other devices arranged outside the power storage system 100. The output fluctuation determination unit 422 may output information indicating the determination result to 430.

In this embodiment, the signal generation unit 430 generates a signal for turning on the switching unit 230 of the power storage module 110 selected by the module selection unit 420. The signal generation unit 430 transmits the generated signal to the module control unit 240. In other embodiments, the signal generation unit 430 may generate a signal for turning off the switching unit 230 of the power storage module 110 selected by the module selection unit 420.

(Discharge prevention control)
In this embodiment, when the signal generation unit 330 outputs the warning signal, the signal generation unit 430 generates a signal (which may be referred to as an input/output control signal) for reducing the magnitude of the current flowing through the power storage module 110 or the switching unit 230 of the power storage module 110 below the second threshold value described in relation to the module control unit 240 in FIG. 2 . For example, the signal generation unit 430 generates the input/output control signal when it receives the warning signal. The signal generation unit 430 may output the generated input/output control signal to the charge/discharge control device 120.

The second threshold may be equal to or less than half the rated current of the switching unit 230, or may be equal to or less than one-quarter the rated current of the switching unit 230. The second threshold may be zero or substantially zero.

In this embodiment, the signal generation unit 430 generates the disconnection control signal described above. The signal generation unit 430 generates the disconnection control signal based on, for example, the determination result of the output fluctuation determination unit 422. The signal generation unit 430 may output the generated disconnection control signal to the module control unit 240.

In one embodiment, if it is determined that fluctuations or decreases in the output of the power storage system 100 are permitted, the signal generating unit 430 generates a disconnection control signal indicating that the off operation of the switching unit 230 is not prohibited, or a disconnection control signal indicating that the off operation of the switching unit 230 is permitted. If it is determined that fluctuations or decreases in the output of the power storage system 100 are not permitted, the signal generating unit 430 generates a disconnection control signal indicating that the off operation of the switching unit 230 is prohibited.

The input/output control signal may be an example of a third signal. The signal generation unit 430 may be an example of a third signal output unit.

Figure 5 shows a schematic diagram of an example of the circuit configuration of the power storage module 110. For the sake of simplicity, the protection unit 250 and the wiring associated with the protection unit 250 are not shown in Figure 5. For the sake of simplicity, the description of the charge state determination unit 312 and the disconnection determination unit 314, as well as the description of the OVP signal and UVP signal, is also omitted in Figure 5.

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 transistors 510 and 520 may be examples of switching elements. In this embodiment, a case will be described in which the transistors 510 and 520 are used as the switching elements of the switching unit 230. 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.

In this embodiment, the module control unit 240 includes a connection determination unit 310, a signal generation unit 330, a switch 592, and a switch 594. In this embodiment, the connection determination unit 310 includes a transistor 530, a resistor 532, a transistor 540, a resistor 542, a resistor 552, and a resistor 554. The signal generation unit 330 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 320.

Next, the details of each part of the switching unit 230 and 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 parasitic diode (not shown) formed equivalently between the source and drain of the transistor 510 allows a current to flow from the positive terminal 212 to the positive terminal 112. Similarly, the transistor 520 is a MOSFET, and even when the transistor 520 is off, a parasitic diode (not shown) formed equivalently between the source and drain of the transistor 520 allows a current to flow from the positive terminal 112 to the positive terminal 212.

In this embodiment, transistors 510 and 520 are initially set to off. When transistor 580 is turned on during charging of the power storage system 100, current flows from the positive terminal 112 to the negative terminal 114 via resistors 512, 514, and transistor 580. As a result, a voltage is applied to the gate of transistor 510, turning transistor 510 on. This allows current to flow from the positive terminal 112 to the positive terminal 212 via a parasitic diode formed equivalently between the source and drain of transistor 520.

On the other hand, when transistor 580 is turned on during discharge of the power storage system 100, current flows from the positive terminal 212 to the negative terminal 214 via resistors 522, 524, and transistor 580. As a result, a voltage is applied to the gate of transistor 520, turning transistor 520 on. This allows current to flow from the positive terminal 212 to the positive terminal 112 via the parasitic diode formed equivalently between the source and drain of transistor 510.

The voltage applied to the gate of transistor 510 or transistor 520 when transistor 580 is turned on may be an example of a signal for turning on the switching element of switching unit 230. Similarly, the voltage applied to the gate of transistor 510 or transistor 520 when transistor 580 is turned off may be an example of a signal for turning off the switching element of switching unit 230.

In this embodiment, the values of resistors 512 and 514 are set so that transistor 510 can be reliably turned on/off while saving power. Furthermore, the values of resistors 522 and 524 are set so that transistor 520 can be reliably turned on/off while saving power.

In this embodiment, a diode 516 is disposed between resistor 514 and resistor 524. Diode 516 allows current to pass in the direction from resistor 514 to resistor 524, but does not allow current to pass in the direction from resistor 524 to resistor 514. By providing diode 516, it is possible to prevent current from leaking from positive terminal 212 to positive terminal 112 through the route of resistor 522, resistor 524, resistor 514, and resistor 512 when switching unit 230 electrically disconnects positive terminal 112 from positive terminal 212.

In this embodiment, a diode 526 is disposed between resistor 514 and resistor 524. Diode 526 allows current to pass in the direction from resistor 524 to resistor 514, but does not allow current to pass in the direction from resistor 514 to resistor 524. By providing diode 526, it is possible to prevent current from leaking from positive terminal 112 to positive terminal 212 through the route of resistor 512, resistor 514, resistor 524, and resistor 522 when switching unit 230 electrically disconnects positive terminal 112 from positive terminal 212.

In the module control unit 240 of this embodiment, transistors 530 and 540 of the connection determination unit 310 are initially set to off. Furthermore, transistors 560 and 580 of the signal generation unit 330 are initially set to off.

According to this embodiment, the value of resistor 532 is set so that transistor 530 turns on when the terminal voltage of switching unit 230 is smaller than a predetermined first value, with positive terminal 112 being positive. The value of resistor 532 is preferably set so that leakage current is minimized when switching unit 230 is off. Furthermore, the value of resistor 542 is set so that transistor 540 turns on when the terminal voltage of switching unit 230 is greater than a predetermined second value. The value of resistor 542 is preferably set so that leakage current is minimized when switching unit 230 is off. Note that, according to this embodiment, the terminal voltage of switching unit 230 is equal to the voltage difference between positive terminal 112 and positive terminal 212.

When the voltage between the terminals of the switching unit 230 is smaller than a predetermined first value, the transistor 530 turns on, and a voltage is applied to the base of the transistor 560 from the storage unit 210 via the positive terminal 212, the transistor 530, and the resistor 552, turning the transistor 560 on. Although the voltage from the positive terminal 112 is applied to the base of the transistor 580, the on-state of the transistor 580 is prevented while the transistor 560 is on. As a result, the transistor 580 turns off.

On the other hand, when the voltage between the terminals of the switching unit 230 is greater than a predetermined second value, transistor 540 is turned on, and voltage is applied from the positive terminal 112 to the base of transistor 560 via transistor 540 and resistor 554, turning transistor 560 on. As a result, transistor 580 is turned off.

In this embodiment, the value of resistor 552 is set so as to reduce power consumption within a range that allows transistor 560 to be turned on when transistor 530 is on. The value of resistor 554 is set so as to reduce power consumption within a range that allows transistor 560 to be turned on when transistor 540 is on.

The capacitance of capacitor 570 is set so that transistor 560 turns on before transistor 580 turns on when voltage from positive terminal 112 is applied to the base of transistor 580. This allows signal generation unit 330 to generate a signal a predetermined time after connection determination unit 310 determines whether the voltage between the terminals of the switching element is within a predetermined range.

In contrast, when the terminal voltage of the switching unit 230 is within the range defined by the first value and the second value, transistors 530 and 540 remain off, and transistor 560 also remains off. As a result, voltage is applied from the positive terminal 112 to the base of transistor 580 via resistor 572, turning on transistor 580.

Switches 592 and 594 may be manual switches, or may be switching elements such as relays, thyristors, or transistors. A signal 52 indicating that switching unit 230 should be turned on may be input to switch 592. A signal 54 indicating that switching unit 230 should be turned off may be input to switch 594.

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

Figure 6 shows an example of the circuit configuration of the module control unit 240. In this embodiment, the module control unit 240 includes a window comparator 642 and a logical product circuit 644.

In this embodiment, the non-inverting input terminal of the window comparator 642 receives, for example, the voltage of the positive terminal 112, and the inverting input terminal of the window comparator 642 receives, for example, the voltage of the positive terminal 212. As a result, if the difference between the positive terminal 112 and the positive terminal 212 is within the allowable connection range, the window comparator 642 outputs a logic "H." On the other hand, if the difference between the positive terminal 112 and the positive terminal 212 is not within the allowable connection range, the window comparator 642 outputs a logic "L."

In this embodiment, if the difference between the positive terminal 112 and the positive terminal 212 is within the connection allowance range and the module control unit 240 is not receiving an OVP signal or a UVP signal, the logical product circuit 644 outputs a logical "H." If the difference between the positive terminal 112 and the positive terminal 212 is not within the connection allowance range, or if the module control unit 240 is not receiving at least one of an OVP signal or a UVP signal, the logical product circuit 644 outputs a logical "L."

Figure 7 shows a schematic diagram of an example of the circuit configuration of the discharge prevention circuit 720. According to this embodiment, the discharge prevention circuit 720 is arranged in parallel with the switching unit 230. The discharge prevention circuit 720 is an element or circuit for preventing arc discharge in the switching unit 230, and its circuit configuration is not particularly limited. In this embodiment, the discharge prevention circuit 720 is an RC snubber circuit and includes a resistor 722 and a capacitor 724. The snubber circuit can absorb transient high voltages that occur when the switch is turned off. This suppresses arc discharge in the switching unit 230. Note that the snubber circuit is not limited to the RC snubber circuit shown in Figure 7, and any known snubber circuit can be used.

In another embodiment, a switching element may be arranged between the resistor 722 and the terminal of the switching unit 230 on the side of the positive terminal 112. A switching element may be arranged between the capacitor 724 and the terminal of the switching unit 230 on the side of the positive terminal 212. These switching elements may be turned on when a warning signal is output. These switching elements may be turned off when the warning signal is released or when the disconnection permission condition is met.

An example of the operation of the power storage system 100 will be described using Figures 8, 9, 10, and 11. Figure 8 schematically shows an example of the operation of the power storage system 100. Figures 9 and 10 schematically show an example of the operation and information processing of the power storage module 110. Figure 11 schematically shows another example of the operation and information processing of the power storage module 110.

Details of each step described in relation to Figure 8 will be described in relation to Figures 9 and 10. In Figures 9 and 11, the operation and information processing of the storage module 110 may be described using the symbols of each step in the embodiment described in relation to Figure 8.

In the embodiment shown in FIG. 8, an example of the operation of the energy storage system 100 is described using as an example a case where a storage module 110 (sometimes referred to as a target module) that has reached the full charge time or end-of-discharge time is removed from the energy storage system 100. More specifically, an example of a process for electrically disconnecting the energy storage unit 210 of the target module from the wiring 106 of the energy storage system 100 in preparation for removal of the target module is described.

According to this embodiment, first, in step 810 (sometimes abbreviated as S), the energy storage system 100 detects that one of the multiple energy storage modules 110 included in the energy storage system 100 (i.e., the target module) is approaching the time to fully charge or the time to end discharge. When it is detected that the energy storage module 110 is approaching the time to fully charge or the time to end discharge, in S812, the energy storage system 100 outputs a warning signal.

When the warning signal is output, in S814, the power storage system 100 stops the input/output of the charge/discharge control device 120 or reduces the input/output current of the charge/discharge control device 120. As a result, the magnitude of the current flowing through the target module also decreases. When the magnitude of the current flowing through the target module becomes sufficiently small, in S816, the power storage system 100 electrically disconnects the power storage unit 210 of the target module from the power storage system 100.

Then, in S818, the energy storage system 100 resumes input and output to the charge/discharge control device 120, or restores the input and output currents of the charge/discharge control device 120. This prevents arc discharge in the switching unit 230 of the target module when the energy storage system 100 disconnects the target module from the energy storage system 100.

As shown in FIG. 9, in S810, the module control unit 240 of each of the multiple energy storage modules 110 included in the energy storage system 100 monitors the voltage of the energy storage unit 210 of each energy storage module. The module control unit 240 may also monitor the voltage of each of the multiple energy storage cells included in the energy storage unit 210.

In one embodiment, the module control unit 240 of the target module detects that the absolute value of the difference between the current voltage value of the storage unit 210 of the target module and the full charge voltage or discharge end voltage has fallen below a predetermined value. When the absolute value of the difference falls below the predetermined value, it is determined that the voltage of the storage unit 210 has reached the first threshold.

In another embodiment, the module control unit 240 detects that the absolute value of the difference between the current value of the voltage of at least one of the multiple storage cells of the storage unit 210 and the full charge voltage or the end-of-discharge voltage has become equal to or less than a predetermined value. When the absolute value of the difference becomes equal to or less than the predetermined value, it is determined that the voltage of the storage unit 210 has reached the first threshold value.

If it is determined that the voltage of the above-mentioned power storage unit 210 has reached the first threshold, in S812 the module control unit 240 of the target module outputs a warning signal to the system control unit 140. When the system control unit 140 receives the warning signal, in S814 the system control unit 140 generates an input/output control signal (sometimes referred to as a reduction signal) to stop the input/output of the charge/discharge control device 120 or to reduce the input/output current of the charge/discharge control device 120. The system control unit 140 outputs the generated input/output control signal to the charge/discharge control device 120.

This reduces the magnitude of the input or output current of the energy storage system 100. As a result, for example, the magnitude of the current flowing through the target module or the switching unit 230 of the target module becomes smaller than the second threshold.

Then, when a predetermined time has elapsed since the module control unit 240 of the target module output the warning signal, the disconnection permission condition is met. When the disconnection permission condition is met, in S816, the module control unit 240 of the target module generates a switching control signal to turn off the switching unit 230 of the target module. The module control unit 240 outputs the generated switching control signal to the switching unit 230.

This electrically disconnects the power storage unit 210 of the target module from the power storage system 100. As a result, the user of the power storage system 100 can remove the target module from the power storage system 100 when it has reached the time to fully charge or to end discharge.

When the power storage unit 210 of the target module is electrically disconnected from the power storage system 100, in S818, the system control unit 140 generates an input/output control signal (sometimes referred to as a recovery signal) to resume input/output to the charge/discharge control device 120 or to restore the input/output current of the charge/discharge control device 120. The system control unit 140 outputs the generated input/output control signal to the charge/discharge control device 120. This resumes charging and discharging of the power storage modules 110 other than the target module, out of the multiple power storage modules 110 arranged in the power storage system 100.

Figure 10 shows an example of the operation of the energy storage system 100. For the sake of simplicity, this embodiment describes an example of the charging operation of the energy storage system 100 during the period from time t0 to time t5, taking as an example the case where one of the multiple energy storage modules 110 included in the energy storage system 100 (sometimes referred to as the target module) reaches full charge time.

In this embodiment, for the purpose of simplifying the explanation, an example of the charging operation of the power storage system 100 will be described using an example in which the charging method of the power storage system 100 is a constant current method. However, the charging method of the power storage system 100 is not limited to the constant current method. In other embodiments, any charging method may be adopted.

In this embodiment, an example of the operation of the energy storage system 100 is described using an example in which, at time t0, the switching units 230 of all storage modules 110 are in the ON state, and the upper limit of the permitted connection range of the target module is smaller than the upper limit of the permitted connection range of the other storage modules 110. In this case, when the target module is substantially fully charged, the energy storage unit 210 of the target module is electrically isolated from the energy storage system 100. Meanwhile, charging of the other storage modules 110 continues even after the target module is substantially fully charged. In other words, during the period from time t0 to time t5, the switching units 230 of the other storage modules 110 are always in the ON state.

In FIG. 10, graph 1020 shows (i) fluctuations in the terminal voltage VB of the power storage unit 210 of the target module, and (ii) fluctuations in the voltage (or potential) VL of the wiring 106 electrically connecting the positive terminal 112 of the target module and the charge/discharge control device 120. Graph 1030 shows fluctuations in the state (on or off) of the warning signal PF output by the target module. Graph 1040 shows fluctuations in the magnitude IL of the input or output current of the power storage system 100. Graph 1050 shows fluctuations in the state (on or off) of the switching unit 230 of the target module.

As shown in graph 1020, during the period from time t0 to time t1, the power storage unit 210 of the target module and the wiring 106 of the power storage system 100 are electrically connected. Therefore, voltages VB and VL are the same, and as the charging of the target module progresses, voltages VB and VL also increase. Furthermore, in this embodiment, the magnitude of the charging current is ILO.

As shown in graph 1020, at time t1, VB and VL reach the first threshold VBP. When VB and VL reach the first threshold VBP at time t1, a warning signal PF is output (turned on) at time t1, as shown in graph 1030. When the warning signal PF is output at time t1, the input power of the charge/discharge control device 120 becomes zero at time t2, as shown in graph 1040. When the input power of the charge/discharge control device 120 becomes zero, the switching unit 230 of the target module turns off at time t3, as shown in graph 1050. At this time, the magnitude of the current flowing through the switching unit 230 is zero, preventing arc discharge in the switching unit 230.

After the switching unit 230 of the target module is turned off, processing is executed to resume charging of the energy storage system 100. Specifically, as shown in graph 1040, at time t4, operation of the charge/discharge control device 120 resumes, and the magnitude of the input current to the charge/discharge control device 120 returns to ILO.

In this embodiment, as shown in graph 1030, the warning signal PF is deactivated (turned off) at time t5. However, the timing at which the warning signal PF is deactivated is not particularly limited. The timing at which the warning signal PF is deactivated may be determined arbitrarily.

Figure 11 shows an example of information processing in the energy storage system 100. In Figure 11, steps similar to those described in relation to Figure 9 are assigned the same reference numerals as those assigned to each step in Figure 9.

The embodiment described in relation to Figure 11 differs from the embodiment described in relation to Figure 9 in the following points: (a) after the module control unit 240 outputs a warning signal in S812, the module control unit 240 waits in S1116 to turn off the switching unit 230 until it receives a disconnection permission signal from the system control unit 140; (b) after the module control unit 240 outputs a warning signal in S812, the system control unit 140 determines in S1112 whether the stopping or reduction of the input/output current is prohibited; (c) if it is determined in S1112 that the stopping or reduction of the input/output current is prohibited, the system control unit 140 outputs a disconnection prohibition signal to the module control unit 240 in S1114; and (d) if it is determined in S1112 that the stopping or reduction of the input/output current is not prohibited, the system control unit 140 outputs a disconnection permission signal to the module control unit 240 in S1118. In other respects, the embodiment described in relation to Figure 11 may have a similar configuration to the embodiment described in relation to Figure 9.

Figure 12 shows a schematic diagram of an example of the system configuration of a large-scale power system 1200. In this embodiment, the large-scale power system 1200 includes a positive terminal 1202, a negative terminal 1204, multiple power storage systems 100, a power cable 1212, a power cable 1214, and a communication cable 1216. The large-scale power system 1200 exchanges power with an external device (e.g., a load device 12 or a charging device 14) via the positive terminal 1202 and the negative terminal 1204.

In this embodiment, the power cable 1212 electrically connects the connection terminal 102 of each of the multiple power storage systems 100 to the positive terminal 1202 of the large-scale power system 1200. In this embodiment, the power cable 1214 electrically connects the connection terminal 104 of each of the multiple power storage systems 100 to the negative terminal 1204 of the large-scale power system 1200. In this embodiment, the communication cable 1216 transmits information between the system control units 140 of each of the multiple power storage systems 100.

As described above, according to this embodiment, the magnitude of the input power or output power of the power storage system 100 is reduced before at least one power storage unit 210 of the power storage modules 110 included in the power storage system 100 is electrically disconnected from the power storage system 100. Depending on the environment in which the large-scale power system 1200 is used, the output fluctuations of the large-scale power system 1200 may be limited. For example, it may be required to suppress the magnitude of the output fluctuations of the large-scale power system 1200 within a predetermined numerical range.

According to this embodiment, when the system control unit 140 of one of the multiple power storage systems 100 (sometimes referred to as the target system) determines that the magnitude of the output current of the charge/discharge control device 120 of the target system can be reduced below the second threshold, the signal generation unit 430 of the target system outputs a signal (sometimes referred to as the fourth signal) to the system control unit 140 or charge/discharge control device 120 of the other power storage system 100 to increase the magnitude of the output current of the other power storage system 100. The system control unit 140 of the power storage system 100 that receives the fourth signal controls the charge/discharge control device 120 to increase the magnitude of the output current. The amount of decrease in output power or output current in the target system may be approximately equal to the total amount of increase in output power or output current in the other power storage systems 100. This suppresses output fluctuations in the large-scale power system 1200.

The signal generating unit 430 of the system control unit 140 may be an example of a fourth signal output unit. The large-scale power system 1200 may be an example of a power system.

Figure 13 shows a schematic example of the operation of the large-scale power system 1200. Graph 1320 shows current fluctuations 1322 in the output current of the power storage system 100 that reduces the output current. Graph 1330 shows current fluctuations 1332 in the output current of another power storage system 100. Graph 1340 shows current fluctuations 1342 in the output current of the large-scale power system 1200. As shown in Figure 13, according to this embodiment, output fluctuations of the large-scale power system 1200 are suppressed.

Figure 14 shows an example of a computer 3000 in which multiple aspects of the present invention may be embodied in whole or in part. At least a portion of the power storage system 100 may be realized by the computer 3000. For example, a portion of the power storage module 110 may be realized by the computer 3000. For example, a portion of the module control unit 240 may be realized by the computer 3000. For example, at least a portion of the system control unit 140 may be realized by the computer 3000.

Programs installed on computer 3000 can cause computer 3000 to function as or perform operations associated with an apparatus according to an embodiment of the present invention or one or more "parts" of the apparatus, and/or can cause computer 3000 to perform processes or steps of processes according to an embodiment of the present invention. Such programs can be executed by CPU 3012 to cause computer 3000 to perform specific operations associated with some or all of the blocks in the flowcharts and block diagrams described herein.

The computer 3000 according to this embodiment includes a CPU 3012, RAM 3014, GPU 3016, and display device 3018, which are interconnected by a host controller 3010. The computer 3000 also includes input/output units such as a communications interface 3022, a hard disk drive 3024, a DVD-ROM drive 3026, and an IC card drive, which are connected to the host controller 3010 via an input/output controller 3020. The computer also includes legacy input/output units such as a ROM 3030 and a keyboard 3042, which are connected to the input/output controller 3020 via an input/output chip 3040.

The CPU 3012 operates according to programs stored in the ROM 3030 and RAM 3014, thereby controlling each unit. The GPU 3016 acquires image data generated by the CPU 3012 into a frame buffer provided in the RAM 3014 or into the GPU 3016 itself, and causes the image data to be displayed on the display device 3018.

The communication interface 3022 communicates with other electronic devices via a network. The hard disk drive 3024 stores programs and data used by the CPU 3012 in the computer 3000. The DVD-ROM drive 3026 reads programs or data from the DVD-ROM 3001 and provides the programs or data to the hard disk drive 3024 via the RAM 3014. The IC card drive reads programs and data from an IC card and/or writes programs and data to an IC card.

ROM 3030 stores therein boot programs and the like that are executed by computer 3000 upon activation, and/or programs that depend on the hardware of computer 3000. I/O chip 3040 may also connect various I/O units to I/O controller 3020 via parallel ports, serial ports, keyboard ports, mouse ports, etc.

The programs are provided on a computer-readable storage medium such as a DVD-ROM 3001 or an IC card. The programs are read from the computer-readable storage medium, installed on the hard disk drive 3024, RAM 3014, or ROM 3030, which are also examples of computer-readable storage media, and executed by the CPU 3012. The information processing described in these programs is read by the computer 3000, resulting in cooperation between the programs and the various types of hardware resources described above. An apparatus or method may be configured by implementing the operation or processing of information in accordance with the use of the computer 3000.

For example, when communication is performed between computer 3000 and an external device, CPU 3012 may execute a communication program loaded into RAM 3014 and instruct communication interface 3022 to perform communication processing based on the processing described in the communication program. Under the control of CPU 3012, communication interface 3022 reads transmission data stored in a transmission buffer area provided in RAM 3014, hard disk drive 3024, DVD-ROM 3001, or a recording medium such as an IC card, and transmits the read transmission data to the network, or writes received data received from the network to a reception buffer area or the like provided on the recording medium.

The CPU 3012 may also cause all or a necessary portion of a file or database stored on an external recording medium such as the hard disk drive 3024, DVD-ROM drive 3026 (DVD-ROM 3001), IC card, etc. to be read into the RAM 3014, and perform various types of processing on the data on the RAM 3014. The CPU 3012 may then write the processed data back to the external recording medium.

Various types of information, such as various types of programs, data, tables, and databases, may be stored on the recording medium and may undergo information processing. The CPU 3012 may perform various types of processing on data read from RAM 3014, including various types of operations, information processing, conditional judgment, conditional branching, unconditional branching, information search/replacement, etc., as described throughout this disclosure and specified by the program's instruction sequence, and write the results back to RAM 3014. The CPU 3012 may also search for information in files, databases, etc. on the recording medium. For example, if multiple entries, each having an attribute value of a first attribute associated with an attribute value of a second attribute, are stored on the recording medium, the CPU 3012 may search for an entry whose attribute value of the first attribute matches a specified condition from among the multiple entries, read the attribute value of the second attribute stored in the entry, and thereby obtain the attribute value of the second attribute associated with the first attribute that satisfies a predetermined condition.

The above-described programs or software modules may be stored on computer-readable storage media on or near computer 3000. Recording media such as a hard disk or RAM provided within a server system connected to a dedicated communications network or the Internet can also be used as computer-readable storage media, thereby providing the above-described programs to computer 3000 via the network.

The present invention has been described above using embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be clear to those skilled in the art that various modifications and improvements can be made to the above embodiments. Furthermore, to the extent that they are not technically inconsistent, the details described for a particular embodiment can be applied to other embodiments. It is clear from the claims and other sources that such modifications and improvements can also be included within the technical scope of the present invention.

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 stated as "before," "prior to," or the like, and it should be noted that processes can be performed in any order, unless the output of a previous process is used in a subsequent process. Even if the operational flow in the claims, specifications, and drawings is described using "first," "next," etc. for convenience, this does not mean that it is necessary to perform the processes in that order.

12 Load device, 14 Charging device, 52 Signal, 54 Signal, 100 Energy storage system, 102 Connection terminal, 104 Connection terminal, 106 Wiring, 110 Energy storage module, 112 Positive terminal, 114 Negative terminal, 120 Charging/discharging control device, 140 System control unit, 210 Energy storage unit, 212 Positive terminal, 214 Negative terminal, 222 Energy storage cell, 224 Energy storage cell, 230 Switching unit, 240 Module control unit, 250 Protection unit, 260 Balance correction unit, 310 Connection determination unit, 312 Charging state determination unit, 314 Disconnection determination unit, 320 Receiving unit, 330 Signal generation unit, 340 Module information acquisition unit, 350 Module information storage unit, 360 Module information transmission unit, 410 Status management unit, 420 Module selection unit, 422 Output fluctuation determination unit, 430, signal generation 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, 642, window comparator, 644, logical product circuit, 720, discharge prevention circuit, 722, resistor, 724, capacitor, 1020, graph, 1030, graph, 1040, graph, 1050, graph, 1200, large-scale power system, 1202, positive terminal, 1204, negative terminal, 1212, power cable, 1214 Power cable, 1216 Communication cable, 1320 Graph, 1322 Current fluctuation, 1330 Graph, 1332 Current fluctuation, 1340 Graph, 1342 Current fluctuation, 3000 Computer, 3001 DVD-ROM, 3010 Host controller, 3012 CPU, 3014 RAM, 3016 GPU, 3018 Display device, 3020 Input/output controller, 3022 Communication interface, 3024 Hard disk drive, 3026 DVD-ROM drive, 3030 ROM, 3040 Input/output chip, 3042 Keyboard

Claims (14)

A power storage system,
a plurality of power storage devices connected in parallel;
an adjusting device that adjusts the magnitude of current flowing through the plurality of power storage devices;
a system control unit;
Equipped with
Each of the plurality of power storage devices is
A power storage unit;
a switching device that switches an electrical connection state between a power terminal of each power storage device and the power storage unit;
A switching control device that controls the operation of the switching device,
a first determination unit that determines whether or not the voltage of the power storage unit has reached a predetermined first threshold;
a first signal output unit that outputs a first signal to notify the user that the power storage unit and the power terminal will be electrically disconnected when it is determined that the voltage of the power storage unit has reached the first threshold value;
a second signal output unit that outputs a second signal to the switching device to electrically disconnect the power storage unit and the power terminal when a disconnection permission condition, which is a condition for permitting electrical disconnection of the power storage unit and the power terminal, is satisfied after the first signal output unit outputs the first signal; and
a switching control device including:
and
The system control unit
when the first signal output unit included in the switching control device of one of the plurality of power storage devices outputs the first signal, outputting a reduction signal to the adjustment device to reduce the magnitude of the current flowing through the plurality of power storage devices;
when the power storage unit and the power terminal are electrically disconnected in the one power storage device by the switching device, a restoration signal is output to the adjustment device to restore a magnitude of a current flowing through a power storage device other than the one power storage device among the plurality of power storage devices;
The system control unit
when the first signal output unit included in the switching control device of the one power storage device outputs the first signal and when it is determined that reducing the magnitude of the current flowing through the plurality of power storage devices is prohibited, outputting a disconnection prohibition signal to the switching control device;
outputting a disconnection permission signal to the switching control device when it is determined that the magnitude of the current flowing through the plurality of power storage devices is permitted to be reduced;
The second signal output unit
when the disconnection prohibition signal is received from the system control unit after the first signal output unit outputs the first signal, the first signal output unit waits for output of the second signal to the switching device;
When the disconnection permission signal is received from the system control unit, the second signal is output to the switching device.
Energy storage system. A power storage system,
a plurality of power storage devices connected in parallel;
an adjusting device that adjusts the magnitude of current flowing through the plurality of power storage devices;
a system control unit;
Equipped with
Each of the plurality of power storage devices is
A power storage unit;
a switching device that switches an electrical connection state between a power terminal of each power storage device and the power storage unit;
A switching control device that controls the operation of the switching device,
a first determination unit that determines whether or not the voltage of the power storage unit has reached a predetermined first threshold;
a first signal output unit that outputs a first signal to notify the user that the power storage unit and the power terminal will be electrically disconnected when it is determined that the voltage of the power storage unit has reached the first threshold value;
a second signal output unit that outputs a second signal to the switching device to electrically disconnect the power storage unit and the power terminal when a disconnection permission condition, which is a condition for permitting electrical disconnection of the power storage unit and the power terminal, is satisfied after the first signal output unit outputs the first signal; and
a switching control device including:
and
The system control unit
when the first signal output unit included in the switching control device of one of the plurality of power storage devices outputs the first signal and when it is determined that reducing the magnitude of the current flowing through the plurality of power storage devices is prohibited, outputting a disconnection prohibition signal to the switching control device;
outputting a disconnection permission signal to the switching control device when it is determined that the magnitude of the current flowing through the plurality of power storage devices is permitted to be reduced;
The second signal output unit
when the disconnection prohibition signal is received from the system control unit after the first signal output unit outputs the first signal, the first signal output unit waits for output of the second signal to the switching device;
When the disconnection permission signal is received from the system control unit, the second signal is output to the switching device.
Energy storage system. The system control unit
when the first signal output unit included in the switching control device of the one power storage device outputs the first signal and when it is determined that a reduction in the output of the power storage system is not permitted, outputting the disconnection prohibition signal to the switching control device;
When it is determined that a reduction in the output of the power storage system is permitted, a disconnection permission signal is output to the switching control device.
The power storage system according to claim 1 or 2 . A power storage system,
a plurality of power storage devices connected in parallel;
an adjusting device that adjusts the magnitude of current flowing through the plurality of power storage devices;
a system control unit;
Equipped with
Each of the plurality of power storage devices is
A power storage unit;
a switching device that switches an electrical connection state between a power terminal of each power storage device and the power storage unit;
A switching control device that controls the operation of the switching device,
a first determination unit that determines whether or not the voltage of the power storage unit has reached a predetermined first threshold;
a first signal output unit that outputs a first signal to notify the user that the power storage unit and the power terminal will be electrically disconnected when it is determined that the voltage of the power storage unit has reached the first threshold value;
a second signal output unit that outputs a second signal to the switching device to electrically disconnect the power storage unit and the power terminal when a disconnection permission condition, which is a condition for permitting electrical disconnection of the power storage unit and the power terminal, is satisfied after the first signal output unit outputs the first signal; and
a switching control device including:
and
The system control unit
when the first signal output unit included in the switching control device of one of the plurality of power storage devices outputs the first signal, outputting a reduction signal to the adjustment device to reduce the magnitude of the current flowing through the plurality of power storage devices;
when the power storage unit and the power terminal are electrically disconnected in the one power storage device by the switching device, a restoration signal is output to the adjustment device to restore a magnitude of a current flowing through a power storage device other than the one power storage device among the plurality of power storage devices;
the power storage unit has a plurality of power storage cells connected in series,
the first determination unit determines that the voltage of the power storage unit has reached the first threshold value when the voltage of at least one of the plurality of power storage cells has reached the first threshold value;
The first threshold value is (i) a value obtained by subtracting a predetermined value from a full charge voltage of the at least one storage cell, or (ii) a value obtained by adding a predetermined value to a discharge end voltage of the at least one storage cell.
Energy storage system. A power storage system,
a plurality of power storage devices connected in parallel;
an adjusting device that adjusts the magnitude of current flowing through the plurality of power storage devices;
a system control unit;
Equipped with
Each of the plurality of power storage devices is
A power storage unit;
a switching device that switches an electrical connection state between a power terminal of each power storage device and the power storage unit;
A switching control device that controls the operation of the switching device,
a first determination unit that determines whether or not the voltage of the power storage unit has reached a predetermined first threshold;
a first signal output unit that outputs a first signal to notify the user that the power storage unit and the power terminal will be electrically disconnected when it is determined that the voltage of the power storage unit has reached the first threshold value;
a second signal output unit that outputs a second signal to the switching device to electrically disconnect the power storage unit and the power terminal when a disconnection permission condition, which is a condition for permitting electrical disconnection of the power storage unit and the power terminal, is satisfied after the first signal output unit outputs the first signal; and
a switching control device including:
and
The system control unit
when the first signal output unit included in the switching control device of one of the plurality of power storage devices outputs the first signal, outputting a reduction signal to the adjustment device to reduce the magnitude of the current flowing through the plurality of power storage devices;
when the power storage unit and the power terminal are electrically disconnected in the one power storage device by the switching device, a restoration signal is output to the adjustment device to restore a magnitude of a current flowing through a power storage device other than the one power storage device among the plurality of power storage devices;
The disconnection permission condition is:
(i) a condition that a predetermined time has elapsed after the first signal output unit outputs the first signal;
(ii) a condition that, after the first signal output unit outputs the first signal, a process is executed to reduce the magnitude of the current flowing through the switching device to be less than a predetermined second threshold value;
(iii) a condition in which the first signal output unit outputs the first signal, and the magnitude of the current flowing through the switching device is smaller than the second threshold; and
(iv) a condition in which the first signal output unit outputs the first signal, and the electrical disconnection of the power storage unit and the power terminal is not prohibited or is permitted;
at least one of
Energy storage system. A power storage system,
a plurality of power storage devices connected in parallel;
an adjusting device that adjusts the magnitude of current flowing through the plurality of power storage devices;
a system control unit;
Equipped with
Each of the plurality of power storage devices is
A power storage unit;
a switching device that switches an electrical connection state between a power terminal of each power storage device and the power storage unit;
A switching control device that controls the operation of the switching device,
a first determination unit that determines whether or not the voltage of the power storage unit has reached a predetermined first threshold;
a first signal output unit that outputs a first signal to notify the user that the power storage unit and the power terminal will be electrically disconnected when it is determined that the voltage of the power storage unit has reached the first threshold value;
a second signal output unit that outputs a second signal to the switching device to electrically disconnect the power storage unit and the power terminal when a disconnection permission condition, which is a condition for permitting electrical disconnection of the power storage unit and the power terminal, is satisfied after the first signal output unit outputs the first signal; and
a switching control device including:
and
The system control unit
when the first signal output unit included in the switching control device of one of the plurality of power storage devices outputs the first signal, outputting a reduction signal to the adjustment device to reduce the magnitude of the current flowing through the plurality of power storage devices;
when the power storage unit and the power terminal are electrically disconnected in the one power storage device by the switching device, a restoration signal is output to the adjustment device to restore a magnitude of a current flowing through a power storage device other than the one power storage device among the plurality of power storage devices;
the decrease signal is a third signal for decreasing the magnitude of the current flowing through the switching device below a predetermined second threshold;
Energy storage system. the adjusting device is (i) a unidirectional or bidirectional DC/DC converter, (ii) a unidirectional or bidirectional DC/AC inverter, or (iii) an on/off switch;
power terminals of the adjustment device are electrically connected to the power terminals of the plurality of power storage devices;
The power storage system according to claim 6 . The power storage system according to claim 3 ;
Another power transfer device different from the power storage system;
Wiring for connecting the power storage system and the other power transfer device in parallel;
A power system comprising:
The power storage device is configured to be detachable from the wiring.
Power system. The power storage system includes:
configured to be detachable from the wiring,
and exchanging power with an external device disposed outside the power system via the adjusting device.
The power system of claim 8 . the system control unit determines whether or not a reduction in output of the power storage system is permitted based on the state of the other power transfer device.
The power system of claim 9 . The system control unit
when it is determined that a decrease in the output of the power storage system is permitted, outputting a fourth signal to the other power transfer device to increase the magnitude of the output current of the other power transfer device;
The power system of claim 10 . A control method for a power storage system including a plurality of power storage devices connected in parallel, comprising:
Each of the plurality of power storage devices is
a power storage unit; and a switching device that switches an electrical connection state between a power terminal of each power storage device and the power storage unit,
The control method includes:
a first determination step of determining whether or not a voltage of the power storage unit of one of the plurality of power storage devices has reached a predetermined first threshold value;
a first signal output step of outputting a first signal for notifying the user that the power storage unit and the power terminal in the first power storage device will be electrically disconnected when it is determined that the voltage of the power storage unit included in the first power storage device has reached the first threshold value;
reducing a magnitude of a current flowing through the plurality of power storage devices when the first signal is output in the first signal output step;
a second signal output step of outputting, to the switching device, a second signal for electrically disconnecting the power storage unit and the power terminal when a disconnection permission condition is satisfied in the one power storage device after the first signal is output in the first signal output step, the second signal being for electrically disconnecting the power storage unit and the power terminal;
a step of restoring a magnitude of a current flowing through a power storage device other than the one power storage device among the plurality of power storage devices when the power storage unit and the power terminal are electrically disconnected in the one power storage device by the switching device;
and
the step of reducing the magnitude of the current flowing through the plurality of power storage devices includes a step of outputting a reduction signal for reducing the magnitude of the current flowing through the plurality of power storage devices to an adjustment device that adjusts the magnitude of the current flowing through the plurality of power storage devices;
the decrease signal is a third signal for decreasing the magnitude of the current flowing through the switching device below a predetermined second threshold;
Control method. A control method for a power storage system including a plurality of power storage devices connected in parallel, comprising:
Each of the plurality of power storage devices is
a power storage unit; and a switching device that switches an electrical connection state between a power terminal of each power storage device and the power storage unit,
The control method includes:
a first determination step of determining whether or not a voltage of the power storage unit of one of the plurality of power storage devices has reached a predetermined first threshold value;
a first signal output step of outputting a first signal for notifying the user that the power storage unit and the power terminal in the first power storage device will be electrically disconnected when it is determined that the voltage of the power storage unit included in the first power storage device has reached the first threshold value;
a second signal output step of outputting, to the switching device, a second signal for electrically disconnecting the power storage unit and the power terminal when a disconnection permission condition is satisfied in the one power storage device after the first signal is output in the first signal output step, the second signal being for electrically disconnecting the power storage unit and the power terminal;
and
The control method includes:
a disconnection prohibition signal output step of outputting a disconnection prohibition signal when the first signal is output in the first signal output step and it is determined that reducing the magnitude of the current flowing through the plurality of power storage devices is prohibited;
a disconnection permission signal output step of outputting a disconnection permission signal when it is determined that the magnitude of the current flowing through the plurality of power storage devices is permitted to be reduced;
and
The second signal output step includes:
a step of waiting for output of the second signal to the switching device when the disconnection prohibition signal is output in the disconnection prohibition signal output step after the first signal is output in the first signal output step;
outputting the second signal to the switching device when the disconnection permission signal is output in the disconnection permission signal output step;
A control method comprising: A program for causing a computer to execute the control method according to claim 12 or 13 .