Electricity storage device and current interruption method

Abstract

The invention provides a power storage device and a current interruption method. A power storage device is provided with a power storage device module, a voltage sensor, a current sensor, an explosion fuse, and a controller. The voltage sensor detects a voltage value of the power storage device module. The current sensor detects a value of a current flowing through the power storage device module. The explosion fuse is connected in series with the power storage device module. In the controller, a voltage condition and a current condition are set. The voltage condition is predetermined according to a voltage value detected by the voltage sensor. The current condition is predetermined according to the current value detected by the current sensor. The controller operates the explosion fuse when both a voltage condition and a current condition are satisfied.

Description

TECHNICAL FIELD

[0001] The present application relates to an electric power storage device and a current interruption method. BACKGROUND

[0002] In Japanese Patent Application Publication No. 2022-133241, a contactor for selectively connecting / interrupting a battery is disclosed. The contactor disclosed in the publication includes a subcircuit, a magnetic sensor, and a controller. The subcircuit includes a conductive body portion, a switch, and a fuse connected in series. The magnetic sensor measures a current flowing through the conductive body portion. The contactor further includes a detection unit for detecting an actual open / close of the switch. The controller detects whether an overcurrent state occurs. The controller causes the switch to be open in a case where the overcurrent state is detected. The controller detects whether the main switch is effectively open. The controller causes the fuse to be blown in a case where the switch is still closed.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENTS

[0005] Patent Document 1: Japanese Patent Application Publication No. 2022-133241 SUMMARY

[0006] The present inventors have aimed to further improve the safety of an electric power storage device.

[0007] The electric power storage device disclosed herein is provided with an electric power storage device module, a voltage sensor, a current sensor, an explosion fuse, and a controller. The electric power storage device module includes a plurality of electric power storage devices. The voltage sensor detects a voltage value of the electric power storage device module. The current sensor detects a current value flowing in the electric power storage device module. The explosion fuse is connected in series with the electric power storage device module. The controller causes the explosion fuse to operate. A voltage condition and a current condition are set in the controller. The voltage condition is determined in advance in accordance with the voltage value detected by the voltage sensor. The current condition is determined in advance in accordance with the current value detected by the current sensor. The controller causes the explosion fuse to operate in a case where both the voltage condition and the current condition are satisfied. The safety of the electric power storage device described above is improved. BRIEF DESCRIPTION OF DRAWINGS

[0008] Figure 1 is a schematic view showing an electric power storage device 100.

[0009] Figure 2 is a flowchart showing a process executed in a controller 50.

[0010] Figure 3 is a timing chart of control of operation of an explosion fuse 40 by the controller 50. DETAILED DESCRIPTION

[0011] An embodiment of the technology disclosed herein will be described below with reference to the accompanying drawings. The embodiment described herein is of course not intended to particularly limit the present application. Each drawing is schematically depicted, and does not necessarily reflect reality. In addition, where components / positions that serve the same function are appropriate, the same reference numerals are added as appropriate, and repeated description is omitted as appropriate.

[0012] <Storage device 100>

[0013] Figure 1 is a schematic view showing a storage device 100. As shown in Figure 1 , the storage device 100 is provided with a storage device module 10, a voltage sensor 20, a current sensor 30, a pyro-fuse 40, and a controller 50. The storage device 100, which is also referred to as a storage device package, is a collection body provided with a structure and the like for controlling the storage device in addition to the storage device.

[0014] <Storage device module 10>

[0015] The storage device module 10 includes a plurality of storage devices 10a. The storage device module 10 includes a positive electrode and a negative electrode. The storage device 10a is configured to be able to take out electric power. In the storage device 10a, electric power supplied from a charger 83 is stored. The storage device 10a is connected to a load 81 via a connector 101. The storage device 10a supplies electric power to the load 81.

[0016] In the storage device 10a, a secondary battery that is repeatedly chargeable and dischargeable by moving between a pair of electrodes (positive electrode and negative electrode) via an electrolyte by a charge carrier is included. In the storage device 10a, for example, a lithium ion secondary battery, a nickel-hydrogen battery, or the like is included. In the storage device module 10, the storage devices 10a can be connected in series, can be connected in parallel, or can be connected in a combination of series and parallel. In this embodiment, a storage device module 10 in which a plurality of storage devices 10a are connected in series is used. The storage device module 10 can be one or a plurality of modules.

[0017] In the electric storage device 100, the connectors 101 to 103 are provided. The connector 101 is connected to a connection line 101a extending from the positive electrode of the electric storage module 10 and a connection line 101b extending from the negative electrode of the electric storage module 10. To the connection line 101a, a connection line 102a extending from the connector 102 and a connection line 103a extending from the connector 103 are connected. The connection line 102a branches from the connection line 101a. The connection line 103a branches from the connection line 102a. To the connection line 101b, a connection line 102b extending from the connector 102 and a connection line 103b extending from the connector 103 are connected. The connection lines 102b, 103b branch from the connection line 101b. The connectors 101 to 103 are configured to be connectable to an external connection device 80. The electric storage device 100 is connectable to the connection device 80 via at least any one of the connectors 101 to 103.

[0018] Although not particularly limited, the connection device 80 can be, for example, a load 81, a DC / DC converter 82, a charger 83, or the like. In this embodiment, the electric storage device 100 is connectable to the load 81 via the connector 101. The load 81 is supplied with electric power from the electric storage module 10 of the electric storage device 100. In this embodiment, the load 81 is a load of an electric vehicle, and can be constituted by an electric motor of the vehicle, an inverter, or the like. The electric storage device 100 is not limited to the above-described mode, and can also be applied to devices other than electric storage devices mounted on electric vehicles. The charger 83 is a device capable of supplying electric power to the electric storage module 10. The charger 83 can be a charger that performs rapid charging of the electric storage module 10, or a charger that performs ordinary charging.

[0019] Between the electric storage module 10 and the connectors 101 to 103, a first contactor 60 and a second contactor 70 are provided. The first contactor 60 and the second contactor 70 are used to switch connection and disconnection between the electric storage module 10 and the connection device 80. The first contactor 60 is provided to the connection line 101a extending from the positive electrode of the electric storage module 10 to the side of the connectors 101 to 103. In other words, the first contactor 60 is provided between the positive electrode of the electric storage module 10 and the connectors 101 to 103. The second contactor 70 is provided to the connection line 101b extending from the negative electrode of the electric storage module 10 to the connectors 101 to 103. In other words, the second contactor 70 is provided between the negative electrode of the electric storage module 10 and the connectors 101 to 103.

[0020] The first contactor 60 and the second contactor 70 are configured to be able to switch between an open state and a closed state independently of each other. Although not particularly limited, as the first contactor 60 and the second contactor 70, a mechanical relay, a semiconductor relay, or the like can be used. In the power storage device 100, the power storage device module 10 and the external connection device 80 are electrically connected by both the first contactor 60 and the second contactor 70 being in the closed state. The switching between the open state and the closed state of the first contactor 60 and the second contactor 70 can also be controlled by the controller 50.

[0021] In the power storage device 100, a pre-charge circuit 65 that prevents a surge current from flowing in the connection device 80 and the power storage device module 10 is provided. The pre-charge circuit 65 is connected in parallel with the first contactor 60. The pre-charge circuit 65 is a circuit in which a pre-charge resistor 66 and a pre-charge relay 67 are connected in series. The pre-charge circuit 65 prevents a surge current from flowing when power is supplied from the power storage device 100 to the load 81, when power is supplied from the charger 83 to the power storage device 100, and the like. Hereinafter, the control of the opening and closing of the first contactor 60, the second contactor 70, and the pre-charge relay 67 will be described with reference to the case where the load 81 is started.

[0022] For example, before the load 81 is started, the first contactor 60, the second contactor 70, and the pre-charge relay 67 are in the open state. When the load 81 is started, the second contactor 70 and the pre-charge relay 67 are switched to the closed state. Thus, the load 81 is connected to the power storage device module 10 via the pre-charge circuit 65. At this time, by providing the pre-charge resistor 66 in the pre-charge circuit 65, power is supplied to the load 81 from the power storage device module 10 at a low current. Thereafter, in a state where the potential of the load 81 is raised, the first contactor 60 is brought to the closed state. Next, the pre-charge relay 67 is brought to the open state. Thus, a large current is prevented from flowing when the load 81 is started.

[0023] The voltage value and the current value of the power storage device module 10 are detected by the voltage sensor 20 and the current sensor 30, respectively. In the power storage device 100, an explosion fuse 40 that operates in accordance with the voltage value and the current value of the power storage device module 10 is provided.

[0024] <Voltage Sensor 20>

[0025] The voltage sensor 20 detects the voltage value of the power storage device module 10. The voltage sensor 20 can be either capable of measuring the voltage of the power storage device module 10 or capable of measuring the voltage of one or a plurality of power storage devices 10a that make up the power storage device module 10. In this embodiment, the voltage sensor 20 is configured to be capable of measuring the power storage device module 10 connected in series, respectively. The voltage sensor 20 is configured to be capable of communicating with the controller 50. The voltage of the power storage device module 10 measured by the voltage sensor 20 is transmitted to the controller 50.

[0026] <Current sensor 30>

[0027] The current sensor 30 measures the charge / discharge current flowing in the power storage device module 10. In this embodiment, the current sensor 30 is provided between the power storage device module 10 and the first contactor 60. The position of the current sensor 30 is not particularly limited. The current sensor 30 is configured to be capable of communicating with the controller 50. The charge / discharge current measured by the current sensor 30 is transmitted to the controller 50.

[0028] <Explosive fuse 40>

[0029] The explosive fuse 40 is connected in series with the power storage device module 10. The explosive fuse 40 is a safety device provided in the power storage device 100. The explosive fuse 40 is a powder-type current breaker. The explosive fuse 40 contains powder, and cuts off the conduction path by igniting the powder. The explosive fuse 40 is provided in the conduction path connecting the power storage device module 10 and the connection device 80. The explosive fuse 40 is provided between the connection point 101al connecting the positive electrode side of the first contactor 60 and the pre-charge circuit 65, and the connection point 101a2 branching from the connection line 102a.

[0030] The position where the explosive fuse 40 is provided is not particularly limited as long as the conduction path of the power storage device module 10 can be cut off. The explosive fuse 40 can be provided between the power storage device module 10 and the first contactor 60. The explosive fuse 40 can be provided in the connection line 101b extending from the negative electrode of the power storage device module 10 to the connectors 101 to 103. In the case where a plurality of power storage device modules 10 are connected in series, the explosive fuse 40 can be provided between adjacent power storage device modules 10. The explosive fuse 40 is operated by the controller 50.

[0031] <Controller 50>

[0032] The controller 50 operates the explosion fuse 40 in accordance with a predetermined condition. The controller 50 can be, for example, an ECU (Electronic Control Unit), a computer mounted on a circuit board, or the like. The computer, for example, functions as required in accordance with a predetermined program. Each function of the computer is processed by cooperation of an arithmetic device (also referred to as a processor, a CPU (Central Processing Unit), or an MPU (Micro-Processing Unit)), a storage device (a memory, a hard disk, or the like), and software of the computer.

[0033] The controller 50 includes a communication section 51, a voltage condition setting section 52, a current condition setting section 53, a determination section 54, and an instruction section 55. Each section 51 to 55 of the controller 50 can be implemented by one or a plurality of processors or can be embedded in a circuit. The communication section 51 of the controller 50 is configured to be able to communicate with the voltage sensor 20 and the current sensor 30.

[0034] The communication between the controller 50 and the voltage sensor 20 and the current sensor 30 can be achieved by transmission and reception of signals. The form of the communication between the controller 50 and the voltage sensor 20 and the current sensor 30 is not particularly limited. For example, the controller 50 can receive information (information of the voltage value and information of the current value) transmitted from the voltage sensor 20 and the current sensor 30 as digital signals, analog signals, logic signals, PWM (Pulse Width Modulation) signals, or wireless signals. The controller 50 can receive the information of the voltage value and the information of the current value as different types of signals. For example, the controller 50 can receive the information of the voltage value as a digital signal and the information of the current value as an analog signal. The controller 50 can receive the information of the voltage value and the information of the current value as the same type of signal. For example, the controller 50 can receive the information of the voltage value and the information of the current value as digital signals.

[0035] When the power storage device 100 is started while the power storage device 100 and the connection device 80 are connected, the opening and closing of the first contactor 60, the second contactor 70, and the pre-charge relay 67 can be controlled in the above-described order. The power storage device 100 and the connection device 80 are electrically connected, and the charge and discharge of the power storage device 100 is started. While the power storage device 100 is being charged and discharged, the controller 50 acquires the voltage value V detected by the voltage sensor 20 and the current value I detected by the current sensor 30 using the communication section 51.

[0036] In the controller 50, a voltage condition predetermined based on a voltage value and a current condition predetermined based on a current value are set. The voltage condition is set using the voltage condition setting unit 52. The current condition is set using the current condition setting unit 53. The controller 50 operates the explosive fuse 40 when both the voltage condition and the current condition are satisfied. The voltage condition and the current condition are not limited to one each. The voltage condition setting unit 52 may also set one or more voltage conditions. The current condition setting unit 53 may also set one or more current conditions. Regarding the voltage condition and the current condition, different conditions may be set during discharge (when power is supplied from the storage device module 10 to the load 81, etc.) and during charging (when the charger 83 charges the storage device module 10, etc.).

[0037] An example of processing executed by controller 50 when power storage device 100 is charged or discharged will be described below.

[0038] In this embodiment, as the voltage condition during discharge, "the voltage value V of the power storage device module 10 is equal to or less than a predetermined threshold value Vth ( Figure 3 The lower limit threshold value Vth1 shown is shown in FIG. 1 . In addition, as the current condition, "the current value I of the power storage device module 10 is greater than or equal to a predetermined threshold value Ith" is set. Here, the threshold value Ith is set to a positive value, and the absolute value of the current value I is compared with the threshold value Ith. The determination unit 54 determines whether the absolute value of the current value I and the voltage value V satisfy the conditions determined by the threshold values ​​Vth and Ith, respectively. In this way, the current condition can be determined by comparing the absolute value of the measured current value I with the threshold value Ith, and the voltage condition can be determined by comparing the measured voltage value V with the threshold value Vth.

[0039] In addition, as a voltage condition during charging, "the voltage value V of the power storage device module 10 is equal to or greater than a predetermined threshold value Vth ( Figure 3 The upper limit threshold Vthu)" is shown.

[0040] The direction of current flow is different during discharge and charging, but the threshold value Ith can also be the same value. Therefore, unlike the voltage condition, the current condition can also be set to the same condition during discharge and charging. In addition, without being limited to the above method, the current condition can also be set according to the measured value of the current value I. For example, during discharge (the current is a positive value), it is also possible to set "the current value I is above the predetermined upper limit threshold value Ithu" as the current condition, and during charging (the current is a negative value), it is set "the current value I is below the predetermined lower limit threshold value Ithl". Regarding the current condition, it is also possible to set "the current value I is above the predetermined upper limit threshold value Ithu or the current value I is below the predetermined lower limit threshold value Ithl" regardless of whether it is during discharge or charging.

[0041] Further, in this embodiment, the voltage sensor 20 is configured to be able to detect the voltage values of the plurality of power storage devices 10a respectively. The voltage values V of the plurality of power storage devices 10a respectively are transmitted from the voltage sensor 20 to the controller 50. In the controller 50, the voltage condition is decided in accordance with the voltage value of one of the plurality of power storage devices 10a. Here, the determination section 54 determines whether or not the one of the plurality of power storage devices 10a satisfies the voltage condition (whether or not the voltage value of each of the power storage devices 10a is equal to or lower than the threshold value Vth). The voltage values V of the plurality of power storage devices 10a respectively can be different. In a case where at least one of the plurality of power storage devices 10a satisfies the voltage condition, the determination section 54 determines that the voltage value V satisfies the voltage condition. Further, the determination of the voltage condition is not limited to being determined in accordance with the voltage value V of one of the power storage devices 10a. For example, in a case where the power storage device module 10 is provided, it can also be determined in accordance with the voltage value V of one of the plurality of power storage device modules 10. In addition, the voltage condition can also be determined in accordance with the voltage value V (so-called total voltage) of the plurality of power storage device modules 10 as a whole.

[0042] Figure 2 is a flowchart showing the processing executed in the controller 50. When the charging and discharging of the power storage device 100 is started and the controller 50 has acquired the voltage value from the voltage sensor 20 and the current value from the current sensor 30, the control of whether or not to operate the explosion fuse 40 is started.

[0043] In step S10 (refer to Figure 2 ), the determination section 54 determines whether or not the voltage value V and the current value I satisfy the determination conditions (voltage condition and current condition) respectively. In a case where neither the voltage value V nor the current value I satisfies the voltage condition and the current condition (“No”), the explosion fuse 40 is not operated, and the charging and discharging from the power storage device module 10 is continued to be executed. In a case where any of the voltage value V and the current value I satisfies the condition (“Yes”), it proceeds to step S15 (refer to Figure 2 ).

[0044] In step S15, which of the voltage value V and the current value I satisfies the condition is determined. In step S15, in a case where the current value I is equal to or higher than the threshold value Ith, the current condition is satisfied, and it proceeds to step S20 (refer to Figure 2). In step S20, it is determined whether the voltage value V satisfies the voltage condition. In a case where the voltage value V is higher than the threshold value Vth, the voltage condition is not satisfied ("No"), the explosion fuse 40 does not operate, and the charge and discharge from the power storage device module 10 is continued. In a case where the voltage value V is the threshold value Vth or less, the voltage condition is satisfied ("Yes"), the controller 50 sends a cut-off signal from the instruction section 55 to the explosion fuse 40. The explosion fuse 40 operates in accordance with the received cut-off signal, and the conductive path (in this embodiment, the connection line 101a) is broken.

[0045] In addition, in step S15, in a case where the voltage value V is the threshold value Vth or less, the voltage condition is satisfied, and step S30 is entered (refer to Figure 2 ). In step S30, it is determined whether the current value I satisfies the current condition. In a case where the current value I is lower than the threshold value Ith, the current condition is not satisfied ("No"), the explosion fuse 40 does not operate, and the charge and discharge from the power storage device module 10 is continued. In a case where the current value I is the threshold value Ith or more, the current condition is satisfied ("Yes"), the controller 50 sends a cut-off signal from the instruction section 55 to the explosion fuse 40. The explosion fuse 40 operates in accordance with the received cut-off signal, and the conductive path (in this embodiment, the connection line 101a) is broken.

[0046] Figure 3 is a timing chart of the control of the operation of the explosion fuse 40 by the controller 50. In Figure 3 , the control performed in accordance with the variation of the voltage value V and the current value I when the power is supplied from the power storage device 100 to the load 81 (at the time of discharge of the power storage device 100) is shown. The threshold value Ith is a set value that assumes a current value that flows through an overcurrent. The threshold value Ith can be set to a value that is higher (or more) than a current value that can flow at the time of normal use of the power storage device module 10. The threshold value Vth is a set value that assumes a voltage value that causes overdischarge. The threshold value Vth can be set to a range that can be taken at the time of normal use of the power storage device module 10. As the threshold value Vth, a lower limit threshold value Vthl and an upper limit threshold value Vthu can be set. The lower limit threshold value Vthl and the upper limit threshold value Vthu can be set in accordance with the rated voltage and the maximum charge voltage of the power storage device 10a, and the like.

[0047] In Figure 3 , the variation of the current value I and the voltage value V in a case where the explosion fuse 40 operates in a case where a bad phenomenon occurs in the power storage device 10a, and the like is shown by a solid line, and the variation of the current value I and the voltage value V in a case where the explosion fuse 40 does not operate is shown by a double-dot chain line. Further, Figure 3 only one example of the variation of the voltage value V and the current value I is shown, the voltage value V and the current value I do not necessarily vary as shown in Figure 3 .

[0048] First, the controller 50 that indicates the case where a bad phenomenon occurs in the electrical storage device 10a and the like makes the explosion fuse 40 operate in the manner shown by a solid line in FIG. 10. Figure 3

[0049] After the discharge starts (at time tO), the determination process of step S10 is started. The current flows and supplies the power accumulated to the electrical storage device module 10 to the load 81. The current value I gradually becomes high, and the voltage value V starts to decrease. Neither the current value I nor the voltage value V satisfies the conditions (the current condition and the voltage condition) (determined as "No" in step S10), so the explosion fuse 40 does not operate. Figure 2 In this embodiment, at the time point of time tl, the current value I reaches the threshold value Ith. After time tl, it is determined as "Yes" in step S10. Here, it is determined that the "current condition" is satisfied in step S15. The voltage value V is higher than the threshold value Vth (higher than the lower limit threshold value Vthl and lower than the upper limit threshold value Vthu), so it is determined as "No" in step S20, and the explosion fuse 40 does not operate.

[0050] At the time point of time t2, the current value I is as it is above the threshold value Ith. At the time point of time t2, the voltage value V further decreases and reaches the threshold value Vth (the lower limit threshold value Vthl in this embodiment). After time t2, it is determined as "Yes" in step S20, and the explosion fuse 40 operates.

[0051] In this embodiment, a delay time td elapses from the time when it is determined as "Yes" in step S20 to the time when the controller 50 makes the explosion fuse 40 operate. Therefore, with respect to the explosion fuse 40, at the time point of time t3 that is the time when the delay time td elapses from time t2 when it is determined as "Yes" in step S20, the explosion fuse 40 operates.

[0052] Next, the process in which the electrical storage device module 10 normally operates and the controller 50 does not make the explosion fuse 40 operate (in the manner shown by a double dotted line in FIG. 11) is described.

[0053] Figure 3 As shown by a double dotted line in FIG. 11, in the case where no abnormality occurs in the electrical storage device module 10, the state where the current value I is lower than the threshold value Ith and the voltage value V is higher than the lower limit threshold value Vthl (the voltage value V is higher than the lower limit threshold value Vthl and lower than the upper limit threshold value Vthu) continues. In this case, it is determined as "No" in step S10, so the explosion fuse 40 does not operate.

[0054] As shown by a double dotted line in FIG. 11, in the case where no abnormality occurs in the electrical storage device module 10, the state where the current value I is lower than the threshold value Ith and the voltage value V is higher than the lower limit threshold value Vthl (the voltage value V is higher than the lower limit threshold value Vthl and lower than the upper limit threshold value Vthu) continues. In this case, it is determined as "No" in step S10, so the explosion fuse 40 does not operate. Figure 3

[0055] ​​​Further, the controller 50 can detect noise of the signals (voltage value V or current value I) transmitted from the voltage sensor 20 and the current sensor 30. Due to the noise of the signals, it is sometimes temporarily determined that either one of the voltage value V and the current value I satisfies the condition. At this time, it is determined "Yes" in step S10. In the case where it is determined that the current value I is the threshold value Ith or more due to the noise in step S15, the process proceeds to step S20. The voltage value V is higher than the lower limit threshold value Vthl and lower than the upper limit threshold value Vthu, so it is determined "No" in step S20, and the explosion fuse 40 does not operate. In the case where it is determined that the voltage value V is the lower limit threshold value Vthl or more (or the upper limit threshold value Vthu or more) due to the noise in step S15, the process proceeds to step S30. The current value I is lower than the threshold value Ith, so it is determined "No" in step S30, and the explosion fuse 40 does not operate.

[0056] In the above embodiment, the power storage device 10 includes a plurality of power storage devices 10a. The voltage sensor 20 detects the voltage value V of the power storage device module 10. The current sensor 30 detects the current value I flowing in the power storage device module 10. The explosion fuse 40 is connected in series to the power storage device module 10. The controller 50 operates the explosion fuse 40. In the controller 50, the voltage condition and the current condition are set. The voltage condition is determined in advance in accordance with the voltage value V detected by the voltage sensor 20. The current condition is determined in advance in accordance with the current value I detected by the current sensor 30. The controller 50 operates the explosion fuse 40 in the case where both the voltage condition and the current condition are satisfied. In the above power storage device 100, the condition for operating the explosion fuse 40 is determined in accordance with both the voltage condition and the current condition. Thus, for example, even in the case where the voltage value V and the current value I are erroneously detected due to noise or the like, the explosion fuse 40 does not operate. Therefore, it is possible to more accurately determine whether an abnormality occurs in the power storage device module 10. As a result, it is possible to reduce the possibility that the explosion fuse 40 operates due to a false operation. By appropriately controlling the timing of operating the explosion fuse 40, it is possible to reduce the possibility that the power storage device module 10 stops due to a false operation. As a result, it is possible to improve the safety of the power storage device 100.

[0057] In the above embodiment, the voltage condition is set to "the voltage value V of the power storage device module 10 is lower than the threshold value Vth (the lower limit threshold value Vthl in this embodiment) at the time of discharging" in advance. Thus, it is possible to cut the conduction path using the explosion fuse 40 in the case where an abnormality possibly caused when the power storage device module 10 becomes over-discharged is detected. As a result, it is possible to improve the safety of the power storage device 100.

[0058] In the above embodiment, the voltage condition is set to be "the voltage value of the power storage device module 10 is equal to or higher than the threshold value Vth (the threshold value Vthu which is the upper limit in this embodiment) decided in advance" at the time of charging. Thus, the abnormality possibly caused in the case where the power storage device module 10 becomes overcharged is detected, and the conduction path can be cut off by the explosion fuse 40. As a result, the safety of the power storage device 100 can be improved.

[0059] In the above embodiment, the current condition is set to be "the current value I of the power storage device module 10 is equal to or higher than the threshold value Ith decided in advance". Thus, the abnormality possibly caused in the power storage device 100 can be detected by the common current condition at the time of charging and at the time of discharging. Further, in the case where an overcurrent flows between the power storage device module 10 and the connection device 80, overcharging occurs at the time of charging and overdischarging occurs at the time of discharging at times. In this embodiment, the current condition is set to be "the absolute value of the current value I of the power storage device module 10 is equal to or higher than the threshold value Ith decided in advance", so that the abnormality at the time of charging and at the time of discharging can be easily detected with high precision.

[0060] In the above embodiment, the voltage condition is decided in accordance with the voltage value V of one of the plurality of power storage devices 10a. Thus, in the case where an abnormality occurs in any of the power storage devices 10a included in the power storage device module 10, the explosion fuse 40 can be promptly cut off. Thus, the safety of the power storage device 100 can be improved.

[0061] However, the voltage condition and the current condition set to the controller 50 in order to operate the explosion fuse 40 are not limited to the above examples. Other conditions can be added to the voltage condition and the current condition, and the conditions can be changed to other conditions.

[0062] As the voltage condition, "the voltage value V is out of the detection range" can be set. The out of the detection range means, for example, a case where the voltage value exceeds an upper limit value of detection in at least any of the voltage sensor 20 and the controller 50. The upper limit value of detection can depend on the device characteristics of the voltage sensor 20 and the controller 50 used. The upper limit value of the voltage condition can be a value higher than the above upper limit threshold value Vthu. By adopting the above voltage condition, even in the case where the voltage value V cannot be normally measured due to an abnormality, the explosion fuse 40 is easily operated appropriately.

[0063] As the current condition, it is also possible to set "the current value I is outside the detection range". The outside of the detection range means, for example, a case where the current value exceeds an upper limit value of detection in at least either of the current sensor 30 and the controller 50. The upper limit value of detection can depend on the device characteristics of the current sensor 30 and the controller 50 used. The upper limit value of detection of the current condition can be a value higher than the threshold value Ith described above. By adopting the current condition described above, even in a case where the current value I cannot be normally measured due to an abnormality, the explosion fuse 40 is easily adapted to operate properly.

[0064] The voltage sensor 20 is not limited to a structure that detects the voltage value V and sends a signal to the controller 50. The voltage sensor 20 can also be able to detect at least either of the overcharge and the overdischarge of the power storage device module 10 or the power storage device 10a. For example, the voltage sensor 20 can also be configured to be able to detect the voltage value V. It is also possible to set a threshold value (for example, the threshold value Vth described above) in the voltage sensor 20 in a case where overcharge and overdischarge occur. In this way, it is also possible to configure the voltage sensor 20 to be able to detect the overcharge and the overdischarge that are detected by the controller 50 in the above-described embodiment. Here, it is preferable to configure the voltage sensor 20 to be able to notify the controller 50 of the detection of at least either of the overcharge and the overdischarge when the voltage sensor 20 detects the above-described at least either. The voltage condition can be set to "notification of the detection of at least either of the overcharge and the overdischarge from the voltage sensor 20". By also detecting the overcurrent and the overcharge using the voltage sensor 20, the accuracy of the detection of abnormalities can be improved.

[0065] Likewise, the current sensor 30 is not limited to a structure that detects the current value I and sends a signal to the controller 50. The current sensor 30 can also be able to detect the overcurrent of the power storage device module 10. For example, the current sensor 30 can also be configured to be able to detect the current value I. In the current sensor 30, it is also possible to set a threshold value (for example, the threshold value Ith described above) in a case where an overcurrent occurs. In this way, it is also possible to configure the current sensor 30 to be able to detect the overcurrent that is detected by the controller 50 in the above-described embodiment. Here, it is preferable to configure the current sensor 30 to be able to notify the controller 50 of the detection of the overcurrent when the current sensor 30 detects the overcurrent. The current condition can be set to "notification of the detection of the overcurrent from the current sensor 30". By also detecting the overcurrent using the current sensor 30, the accuracy of the detection of abnormalities can be improved.

[0066] Further, in the controller 50, as the voltage condition, "communication interruption from the voltage sensor 20 to the controller 50" can also be set. Similarly, in the controller 50, as the current condition, "communication interruption from the current sensor 30 to the controller 50" can also be set. These situations can also be determined in a case where the controller 50 does not receive a signal from the sensor (voltage sensor 20, current sensor 30) although the power storage device 100 has been started. By setting the above conditions, it is easier to detect an adverse phenomenon that can occur in the power storage device 100.

[0067] As described above, in the power storage device 100, a plurality of voltage conditions and a plurality of current conditions can also be set. By setting a plurality of conditions, it is easy to cause the explosion fuse 40 to operate in correspondence with various adverse phenomena that can occur in the power storage device 100. As a result, it is possible to improve the safety of the power storage device 100.

[0068] The above describes various technologies disclosed herein. The embodiments and the like recited herein do not limit the present application as long as not particularly mentioned. Further, the technologies disclosed herein can be changed in various ways as long as no particular problem arises, and each component, each process recited herein can be omitted or appropriately combined. Further, the present specification includes the disclosure recited in each of the following items.

[0069] Item 1:

[0070] A power storage device including:

[0071] a power storage device module including a plurality of power storage devices;

[0072] a voltage sensor that detects a voltage value of the power storage device module;

[0073] a current sensor that detects a current value flowing in the power storage device module;

[0074] an explosion fuse connected in series with the power storage device module; and

[0075] a controller that causes the explosion fuse to operate,

[0076] the controller is set with:

[0077] a voltage condition determined in advance from the voltage value detected by the voltage sensor; and

[0078] a current condition determined in advance from the current value detected by the current sensor,

[0079] the explosion fuse is caused to operate in a case where both the voltage condition and the current condition are satisfied.

[0080] Item 2:

[0081] The power storage device according to item 1, wherein

[0082] The voltage condition is set so that the voltage value of the power storage device module is below a threshold value decided in advance at the time of discharging.

[0083] Item 3:

[0084] The power storage device according to item 1 or 2, wherein

[0085] The voltage condition is set so that the voltage value of the power storage device module is above a threshold value decided in advance at the time of charging.

[0086] Item 4:

[0087] The power storage device according to any one of items 1 to 3, wherein

[0088] The current condition is set so that the current value of the power storage device module is above a threshold value decided in advance.

[0089] Item 5:

[0090] The power storage device according to any one of items 1 to 4, wherein

[0091] The voltage condition is decided in accordance with the voltage value of one of the plurality of power storage devices.

[0092] Item 6:

[0093] The power storage device according to any one of items 1 to 5, wherein

[0094] The voltage condition is set so that the voltage value is outside a detection range.

[0095] Item 7:

[0096] The power storage device according to any one of items 1 to 6, wherein

[0097] The current condition is set so that the current value is outside a detection range.

[0098] Item 8:

[0099] The power storage device according to any one of items 1 to 7, wherein

[0100] The voltage sensor is configured to be able to detect at least either of overcharging and overdischarging and to be able to notify the controller of the detection of the at least either of overcharging and overdischarging when the at least either of overcharging and overdischarging is detected,

[0101] The voltage condition is set so that the at least either of overcharging and overdischarging is notified from the voltage sensor.

[0102] Item 9:

[0103] The power storage device according to any one of items 1 to 8, wherein

[0104] The current sensor is configured to be able to notify the controller of detection of the overcurrent in a case where the overcurrent is detected,

[0105] The current condition is set to be notified of detection of the overcurrent from the current sensor.

[0106] Item 10:

[0107] A current cutoff method of cutting off a current flowing in a power storage device module including a plurality of power storage devices, the current cutoff method including:

[0108] detecting a voltage value of the power storage device module;

[0109] detecting a current value flowing in the power storage device module; and

[0110] causing an explosive fuse to operate in a case where a predetermined condition is satisfied,

[0111] the explosive fuse is connected in series with the power storage device module,

[0112] as the predetermined condition, there is set:

[0113] a voltage condition decided in accordance with the voltage value; and

[0114] a current condition decided in accordance with the current value,

[0115] the explosive fuse is caused to operate in a case where both the voltage condition and the current condition are satisfied.

Claims

1. An electric power storage device, comprising: an electric power storage device module including a plurality of electric power storage devices; a voltage sensor that detects a voltage value of the electric power storage device module; a current sensor that detects a current value flowing in the electric power storage device module; an explosion fuse connected in series with the electric power storage device module; and a controller that operates the explosion fuse, the controller being provided with: a voltage condition determined in advance from the voltage value detected by the voltage sensor; and a current condition determined in advance from the current value detected by the current sensor, the explosion fuse being operated in a case where both the voltage condition and the current condition are satisfied.

2. The electric power storage device according to claim 1, wherein the voltage condition is set so that the voltage value of the electric power storage device module is below a threshold value determined in advance at the time of discharging.

3. The electric power storage device according to claim 1, wherein the voltage condition is set so that the voltage value of the electric power storage device module is above a threshold value determined in advance at the time of charging.

4. The electric power storage device according to any one of claims 1 to 3, wherein the current condition is set so that the current value of the electric power storage device module is above a threshold value determined in advance.

5. The electric power storage device according to any one of claims 1 to 3, wherein the voltage condition is determined from a voltage value of one of the plurality of electric power storage devices.

6. The electric power storage device according to any one of claims 1 to 3, wherein the voltage condition is set so that the voltage value is outside a detection range.

7. The electric power storage device according to any one of claims 1 to 3, wherein the current condition is set so that the current value is outside a detection range.

8. The electric power storage device according to any one of claims 1 to 3, wherein the voltage sensor is configured to detect at least either overcharging or overdischarging and to notify the controller of the detection of the at least either overcharging or overdischarging, the voltage condition being set so that the notification of the detection of the at least either overcharging or overdischarging is received from the voltage sensor.

9. The electric power storage device according to any one of claims 1 to 3, wherein the current sensor is configured to detect overcurrent and to notify the controller of the detection of the overcurrent, the current condition being set so that the notification of the detection of the overcurrent is received from the current sensor.

10. A current cutoff method of cutting off a current flowing in an electric power storage device module including a plurality of electric power storage devices, the current cutoff method comprising: detecting a voltage value of the electric power storage device module; detecting a current value flowing in the electric power storage device module; and operating an explosion fuse in a case where a predetermined condition is satisfied, the explosion fuse being connected in series with the electric power storage device module, as the predetermined condition, a voltage condition determined from the voltage value and a current condition determined from the current value being set, the explosion fuse being operated in a case where both the voltage condition and the current condition are satisfied. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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