Energy storage device

Abstract

An energy storage device 20 includes a cell 31; a first current interruption circuit 50 positioned on a current path of the cell 31; a second current interruption circuit 100 connected in parallel to the first current interruption circuit 50 and having a lower current capacity and power consumption than the first current interruption circuit 50; and a control unit 150. The second current interruption circuit 100 includes a current limiting device 140, and in a case where a current of the energy storage device 20 is lower than a predetermined value, the control unit 150 opens the first current interruption circuit 50 and closes the second current interruption circuit 100.

Description

Technical area

[0001] The present invention relates to a technology for reducing the power consumption of the energy storage apparatus. State of the art

[0002] An energy storage device installed in a motor vehicle, etc., has a current interruption circuit, such as a FET. When abnormalities such as overdischarge or overcharge are detected, the energy storage device can be protected by opening the current interruption circuit and interrupting the current. Patent Literature 1 is a document disclosing this type of technology. Citation listPatent literature

[0003] Patent specification 1: WO2011 / 158894 Disclosure of the inventionProblems to be solved by the invention

[0004] An energy storage device outputs different amounts of current depending on its operating state, etc. For example, when parked, a low current is sufficient, whereas in operating states other than parking, such as driving, a higher current than that required for charging and discharging must be applied. If a high current is output, the use of a current interruption circuit with a high current capacity may be considered.

[0005] However, a high-current interruption circuit occasionally consumes high power, and reducing power consumption has become a challenge. Energy storage devices for devices other than vehicles also face the same challenge.

[0006] The present invention seeks to reduce the power consumption of an energy storage device and reduce the probability of failure in a power interruption circuit. Means to solve the problems

[0007] An energy storage device comprises: a cell; a first current interruption circuit positioned on a current path of the cell; a second current interruption circuit connected in parallel to the first current interruption circuit and having a lower current capacity and power consumption than the first current interruption circuit; and a control unit. The second current interruption circuit includes a current limiting device.

[0008] When the current of the energy storage device is lower than a predetermined value, the control unit opens the first current interruption circuit and closes the second current interruption circuit. The current lower than a predetermined value includes the zero current. Effect of the invention

[0009] It is possible to reduce the power consumption of an energy storage device and reduce the failure of a power interruption circuit. Short description of the characters Fig. 1 is a side view of a motor vehicle. Fig. 2 is a perspective view of a battery. Fig. 3 is an exploded perspective view of a battery. Fig. Figure 4 is a block diagram showing an electrical configuration of the battery. Fig. Figure 5 is a circuit diagram when a first circuit is connected in parallel. Fig. 6 shows details of a first drive circuit. Fig. Figure 7 shows details of a second drive circuit. Fig. Figure 8 is a table summarizing the voltage control of a FET. Fig. 9 compares the performance of a first current interruption circuit with that of a second current interruption circuit. Fig. Figure 10 is a flowchart illustrating the switch control of a power interrupt circuit. Fig. Figure 11 is a circuit diagram showing a charging and discharging path during parking. Fig. Figure 12 is a circuit diagram showing a charging and discharging path in conditions other than parking. Fig. Figure 13 is a block diagram showing an electrical configuration of a battery. Description of the Embodiments (Sketch of the present embodiment)

[0010] (1) An energy storage device according to an embodiment of the present invention includes a cell; a first current interruption circuit positioned on a current path of the cell; a second current interruption circuit connected in parallel to the first current interruption circuit and having a lower current capacity and power consumption than the first current interruption circuit; and a control unit. The second current interruption circuit includes a current limiting device.

[0011] When the current of the energy storage device is lower than a predetermined value, the control unit opens the first current interruption circuit and closes the second current interruption circuit. The current lower than a predetermined value includes the zero current.

[0012] According to the energy storage device according to an embodiment of the present invention, when the current is lower than a predetermined value, the control unit opens the first high-power current interruption circuit and closes the second low-power current interruption circuit, which contributes to reducing the power consumption of the energy storage device. Since the second current interruption circuit includes a current-limiting device, the current can be limited even if external short circuits or other abnormalities occur while the second current interruption circuit is closed. This can reduce the failure of the second current interruption circuit.

[0013] (2) In the energy storage apparatus as described above (1), a configuration is possible in which the current limiting device is a current limiting resistor and the control unit measures the current based on the voltage at two terminals of the current limiting resistor.

[0014] In the energy storage device described in (2), a high voltage is generated at a low current by using a high resistance for the current-limiting resistor. This enables the measurement of a low current with high accuracy.

[0015] (3) In the energy storage apparatus as described in (2) above, a configuration is possible in which the energy storage apparatus includes a current sensor that measures the current of the energy storage apparatus, and the control unit corrects a measured current value of the current sensor based on a measured current value of the current limiting device.

[0016] According to the energy storage device described in (3), the current measurement accuracy of the current sensor can be improved. By improving the current measurement accuracy, the estimation accuracy of the SOC calculated based on the measured current value can be improved.

[0017] (4) In the energy storage device described in any one of (1) to (3) above, a configuration is possible in which, in a case where the current of the energy storage device is the predetermined value or higher, the control unit closes the first current interruption circuit and opens the second current interruption circuit. According to the energy storage device described in (4), the current of a predetermined value or higher flows through the first current interruption circuit with a high current capacity and does not flow through the second current interruption circuit with a low current capacity. Therefore, overheating of the second current interruption circuit is prevented.

[0018] (5) In the energy storage apparatus as described in any one of the above items (1) to (4), a configuration is possible in which the first current limiting circuit comprises: an N-channel FET arranged on a high side of the cell; and a first drive circuit that drives the N-channel FET, and the second current limiting circuit comprises: a P-channel FET connected in parallel to the N-channel FET; a second drive circuit that drives the P-channel FET; and the current limiting device.

[0019] According to the energy storage device described in (5), the N-channel FET is arranged on a high side of the cell. The energy storage device in which the N-channel FET is arranged on a high side of the cell must continuously apply a higher voltage to the gate than to the cell to keep the FET in a closed state. Therefore, the power consumption of the first drive circuit for driving the FET is high. When the present invention is applied to an energy storage device in which the N-channel FET is arranged on a high side of the cell, the power consumption of the first drive circuit can still be reduced by using the P-channel FET when the current is lower than a predetermined value.

[0020] (6) The energy storage device described in any of (1) to (5) above may be for use with a vehicle. A configuration is possible in which the control unit opens the first power interruption circuit and closes the second power interruption circuit when the vehicle is parked.

[0021] The energy storage device described in (6) can reduce power consumption during parking.

[0022] (7) The energy storage device described in any one of (1) to (6) above may be designed for use with a vehicle. A configuration is possible in which the control unit opens the first power interruption circuit and closes the second power interruption circuit when the energy storage device is not mounted on a vehicle or when the energy storage device is removed from a vehicle.

[0023] The energy storage device described in (7) can reduce the standby power in cases where the energy storage device is de-energized, such as before the energy storage device is mounted on a vehicle or when the energy storage device is removed from a vehicle. <Erste Ausführungsform> 1. Description of the battery

[0024] Fig. 1 is a side view of a motor vehicle, Fig. 2 is a perspective view of a battery, Fig. 3 is an exploded perspective view of a battery, and Fig. Figure 4 is a block diagram illustrating an electrical configuration of the battery. Fig. 1 only shows a motor vehicle 1 and a battery 20, but no other component of which the motor vehicle consists is shown.

[0025] As in Fig. 1, the automobile (an example of a vehicle) 1 includes a battery 20, which is an energy storage device. As shown in Fig. 2, the battery 20 includes a battery case 21 in block form, and an assembled battery 30 and a circuit board 200 consisting of a plurality of cells 31 are housed in the battery case 21.

[0026] In the following description, if you look at Fig. 2 and Fig. 3, an up-down direction of the battery case 21 when the battery case 21 is placed in a horizontal orientation without being tilted with respect to a mounting surface is assumed as a Y direction; a direction along a long side direction of the battery case 21 is assumed as an X direction; and a depth direction of the battery case 21 is assumed as a Z direction.

[0027] As in Fig. As shown in Figure 3, the battery case 21 includes: a box-shaped case main body 23 that opens upward; a positioning member 24 for positioning the plurality of cells 31; an inner lid 25 that is attached to an upper part of the case main body 23; and an upper lid 29 that is attached to an upper part of the inner lid 25. Inside the case main body 23, a plurality of cell chambers 23A, in which cells 31 are separately housed, are arranged in the X direction.

[0028] As in Fig. 3, a plurality of bus bars 24A are aligned on an upper surface of the positioning member 24, and the positioning member 24 is arranged on an upper portion of the plurality of cells 31 aligned in the case main body 23. Therefore, the plurality of cells 31 are positioned and connected in series by the plurality of bus bars 24A.

[0029] As in Fig. As shown in Figure 3, the inner cover 25 has a rectangular shape in plan view and is provided at both ends in the X direction with a pair of external terminals 22P and 22N, which are connected to unillustrated wire harness terminals. The pair of external terminals 22P and 22N are made of metal such as a lead alloy, for example, and 22P represents a positive electrode and 22N represents a negative electrode.

[0030] As in Fig. 3, the circuit board 200 is arranged on an upper surface of the inner cover 25, and the upper cover 29 closes the upper part thereof.

[0031] Fig. Figure 4 is a block diagram showing an electrical configuration of the battery 20. The battery 20 includes an assembled battery 30, a voltage measurement unit (not shown), a current sensor 40, a temperature sensor 45, a first power interruption circuit 50, a second power interruption circuit 100, and a management device 150.

[0032] The assembled battery 30 has, for example, four cells 31 (see Fig. 2) connected in four series. The cell is not limited to a prismatic cell, but can also be a cylindrical cell or a pouch cell with a laminated foil casing. Cell 31, for example, is a lithium-ion secondary battery cell.

[0033] The assembled battery 30, the current sensor 40 and the first current interruption circuit 50 are connected in series via the power line 35P and the power line 35N.

[0034] As in Fig. As shown in Figure 4, the power supply line 35P connects the external terminal of the positive electrode 22P to the positive electrode of the assembled battery 30. The power supply line 35N connects the negative electrode of the external terminal 22N to the negative electrode of the installed battery 30. The external terminals 22P and 22N are terminals for connection to the motor vehicle 1 and can establish an electrical connection to a load 15 or an alternator 16 mounted in the vehicle via the external terminals 22P and 22N. The load 15 includes an engine starting device and auxiliary machines.

[0035] Current sensor 40 is attached to negative power line 35N. Current sensor 40 may be a shunt resistor. Resistor-type current sensor 40 may measure the current I of the assembled battery 30 based on the voltage across two terminals of a resistor. Alternatively, current sensor 40 may also be a magnetic sensor.

[0036] The voltage measuring unit (not shown) measures the voltage of the installed battery 30. The temperature sensor 45 is attached to the installed battery 30 and detects the temperature of the installed battery 30 or its surroundings.

[0037] The first current interrupt circuit 50 is mounted on the circuit board 200 and arranged on the positive power line 35P. The first current interrupt circuit 50 is a circuit for interrupting the current I from the battery 20. The first current interrupt circuit 50 will be explained in more detail below.

[0038] The management device 150 is mounted on the circuit board 200 and includes, as shown in Fig. 4, a CPU 151, a memory 153 and a communication unit 155. The management device 150 corresponds to a "control unit" in the sense of the present invention.

[0039] The management device 150 monitors the state of the battery 20 based on the outputs of the voltage measuring unit, the current sensor 40, and the temperature sensor 45. The management device 150 calculates the SOC [%] of the battery 20 based on the current I of the battery 20. The SOC (State of Charge) is a ratio of the remaining capacity [Ah] to the full charge capacity [Ah].

[0040] The communication unit 155 is used for communication and connection with the electronic control unit of the vehicle 16. The electronic control unit (vehicle ECU) 16 is mounted on the vehicle 1 and controls the vehicle 1. The management device 150 can obtain information about the state of the vehicle 1 (parking, driving, stopping, etc.) by communicating with the vehicle ECU 16.

[0041] The memory 153 stores a monitoring program for the battery 20, a switching program for the power interruption circuits 50 and 100, and the data required to execute these programs.

[0042] The program may be stored on a recording medium such as a CD-ROM for use, transmission, rental, or the like. The program may be distributed via a telecommunications line. 2. Configuration of the first power interruption circuit 50 and the second power interruption circuit 100

[0043] The first current interruption circuit 50 is located in the positive electrode (high side) of the assembled battery 30 and includes a first changeover circuit 60 and a first drive circuit 70.

[0044] The first switching circuit 60 is an N-channel field-effect transistor (FET). In the present embodiment, the first switching circuit 60 includes two FETs 61A and 61B.

[0045] A drain of FET 61A is connected to a positive electrode of the assembled battery 30, and a drain of FET 61B is connected to a positive electrode of the external terminal 22P. The respective sources of the two FETs 61A and 61B are connected to each other, and the two FETs 61A and 61B are connected back-to-back. A back-to-back connection is a connection between the drains or sources of two FETs.

[0046] As in Fig. As shown in Figure 5, the first current interruption circuit 50 may take a form in which a plurality of first alternating circuits 60 are connected in parallel. By connecting the plurality of first alternating circuits 60 in parallel, the current capacity [A] of the first current interruption circuit 50 can be increased.

[0047] Fig. 6 shows details of a first drive circuit 70 (the second drive circuit 120 is not shown). The first drive circuit 70 is a drive circuit of the first changeover circuit 60. The first drive circuit 70 operates with the built-in battery 30 as a power source and includes two IC circuits 71A and 71B. The IC circuit 71A drives the FET 61A, and the IC circuit 71B drives the FET 61B.

[0048] The IC circuit 71A includes a gate driver IC 73A that drives a gate of the first switching circuit 60 and its peripheral circuitry. The gate driver IC 73A includes an output terminal P for applying a high voltage to a gate. The peripheral circuitry includes a gate resistor 74A, a Zener diode 75A, a capacitor 76A, an inductor 77A, a capacitor 78A, and the like. A line LG represents a voltage reference line, and a line LO represents an output line for a control signal.

[0049] Zener diode 75A serves to stabilize the gate voltage. Capacitor 76A, inductor 77A, and capacitor 78A each serve as a filter. IC circuit 71B has the same configuration as IC circuit 71A.

[0050] The management device 150 applies a predetermined positive voltage to the gate of the FET 61A via the gate driver IC 73A to control the FET 61A to be closed when Vgs≥Vgs(th). The predetermined positive voltage is, for example, a voltage approximately 10 V higher than a positive electrode voltage of 12 V of the assembled battery 30 and approximately 20 V. Vgs(th) is a threshold voltage of the FET 61A and the FET 61B.

[0051] The management device 150 can control the FET 61A to be in an open state by controlling the gate voltage through the gate driver IC 73A so that Vgs<Vgs(th). Furthermore, the management device 150 can control the FET 61B to be in a closed or open state by controlling the gate voltage of the FET 61B through the gate driver IC 73B.

[0052] As in Fig. As shown in Figure 4, the second power interruption circuit 100 is connected in parallel with the first power interruption circuit 50. The second power interruption circuit 100 includes a second switching circuit 110 and a second drive circuit 120.

[0053] The second switching circuit 110 is a P-channel field-effect transistor (FET). In the present embodiment, the second switching circuit 110 includes two FETs 111A and 111B.

[0054] A source of FET 111A is connected to the positive electrode of the assembled battery 30, and a source of FET 111B is connected to the external positive electrode terminal 22P. The respective drains of the two FETs 111A and 111B are connected to each other, and the two FETs 111A and 111B are in back-to-back connection. The two FETs 111A and 111B are closed by controlling the gate voltage by the second drive circuit 120 so that Vgs≤-Vgs(th). The two FETs 111A and 111B are opened by controlling the gate voltage so that Vgs>-Vgs(th). Vgs(th) is a threshold voltage of the FETs 111A and 111B.

[0055] Fig. 7 is a circuit diagram of the second drive circuit 120 (the first drive circuit 70 is not shown). The second drive circuit 120 is a drive circuit of the second changeover circuit 110. The second drive circuit 120 operates with the assembled battery 30 as a power source and includes, as shown in Fig. 7, a switch 121, gate resistors 123A and 123B, diodes 124A and 124B, gate-source resistors 125A and 125B, and Zener diodes 126A and 126B.

[0056] Switch 121 is an N-channel FET. Gate resistor 123A connects a gate of FET 111A to a drain of switch 121. Diode 124A is arranged between the gate of FET 111A and the drain of switch 121. Diode 124A has an anode connected to the gate of FET 111A and a cathode connected to the drain of switch 121.

[0057] Gate-source resistor 125A is connected between the gate and source of FET 111A. Gate resistor 123A and gate-source resistor 125A form a voltage divider circuit.

[0058] When switch 121 is turned ON, a current IG1 flows through a path along the assembled battery 30, the gate-source resistor 125A, the gate resistor 123A, the diode 124A, and the switch 121, and a voltage divided by a positive electrode voltage of the assembled battery 30 is generated at the gate of the FET 111A. As a result, the FET 111A is brought into the state Vgs≤-Vgs(th), and the FET 111A is closed.

[0059] When the switch 121 is turned on, the gate voltage of the FET 111B decreases, and the FET 111B is also brought into the state Vgs≤-Vgs(th), similar to the FET 111A, and the FET 111B is closed.

[0060] Therefore, in addition to the above-mentioned path, a current IG2 flows through a path along the assembled battery 30, the FETs 111A and 111B, the gate-source resistor 125B, the gate resistor 123B, the diode 124B, and the switch 121. The current IG1, IG2 maintains the state Vgs≤-Vgs(th), and the two FETs 111A and 111B are kept in the closed state.

[0061] When a combined resistance value of the gate resistor 123A and the gate-source resistor 125A increases, the current IG1, IG2 decreases, and the power consumption of the second drive circuit 120 can be reduced (the same applies to a case where a combined resistance value of the gate resistor 123B and the gate-source resistor 125B increases).

[0062] When switch 121 is turned OFF, current IG1 is cut off, so Vgs>-Vgs(th), and FET 111A therefore opens. Similar to FET 111A, FET 111B can also be controlled to open when switch 121 is turned OFF.

[0063] The second current interruption circuit 100 includes, in addition to the second switching circuit 110 and the second drive circuit 120, a current limiting resistor 140. The current limiting resistor 140 is connected in series with the second switching circuit 110 and limits the current I of the second current interruption circuit 100. In one example, the current limiting resistor 140 is a high resistance of approximately 100 Ω.

[0064] Fig. Figure 9 compares the performance of the first current interruption circuit 50 and the second current interruption circuit 100. The first current interruption circuit 50 and the second current interruption circuit 100 differ in current capacity and power consumption. The second current interruption circuit 100 has a lower current capacity than the first current interruption circuit 50 and a lower power consumption when closed. The current capacity is the maximum current that can flow through the current interruption circuit and is specified in [A].

[0065] The reason why the two current interruption circuits 50 and 100 differ in current capacity and power consumption is that the switching circuits 60 and 110 use different FET channels. Specifically, the first switching circuit 60 of the first current interruption circuit 50 uses an N-channel FET, which has a low on-resistance between source and drain, and therefore the current capacity is high. Since the N-channel FET is arranged on a high side (positive electrode side) of the assembled battery 30, to maintain the closed state, a voltage of approximately 20 V must be constantly applied to the gate by the gate driver IC or a booster converter, so the power consumption of the first drive circuit 70 becomes high.

[0066] Fig. 10 is a flowchart illustrating the switching control of a power cut circuit. The switching control of the power cut circuit consists of four steps from S10 to S40, which are executed, for example, when communication with the vehicle ECU 16 begins when the battery 20 is installed in the vehicle.

[0067] When the control of the switch by the power cut circuit starts, the management device 150 accesses the vehicle ECU 16 and detects the state of the vehicle 1. In the present embodiment, the detected state of the vehicle 1 is whether the vehicle 1 is parked or in another state.

[0068] During parking, the current supplied by the battery 20 to the vehicle 1 is a low current, ie a current below a predetermined value (e.g. below 100 mA).

[0069] When the vehicle 1 is parked, the management device 150 closes the P-channel FETs 111A and 111B of the second power interruption circuit 100 and opens the N-channel FETs 61A and 61B of the first power interruption circuit 50 (S30).

[0070] Accordingly, the battery 20 charges and discharges on a path along the P-channel FETs 111A and 111B of the second current interruption circuit 100 when the vehicle 1 is parked, as shown in Fig. 11 shown.

[0071] When N-channel FETs 61A and 61B are open, the gate does not need to be maintained at a high voltage. Therefore, it is possible to reduce the power consumption of the first drive circuit 70 during parking.

[0072] The second current interruption circuit 100 includes a current limiting resistor 140 connected in series with the P-channel FETs 111A and 111B. By including the current limiting resistor 140, even if external short circuits or other abnormalities occur while the second current interruption circuit 100 is closed, no abnormally high current flows through the P-channel FETs 111A and 111B, and the probability of failure of the second current interruption circuit 100 can be reduced.

[0073] While the motor vehicle 1 is traveling or in conditions other than when the motor vehicle 1 is parked, the current I supplied by the battery 20 to the motor vehicle 1 is higher than when the motor vehicle 1 is parked and is a predetermined value or more (e.g., several amperes (A)).

[0074] While the vehicle 1 is traveling or in states other than the parked state, the management device 150 of the first power interrupt circuit 50 closes and opens the second power interrupt circuit 100 (S40). Accordingly, the battery 20 charges and discharges along a path along the N-channel FETs 61A and 61B of the first power interrupt circuit 50 when the vehicle 1 is in states other than the parked state, as shown in Fig. 12 shown.

[0075] Since the N-channel FETs 61A and 61B of the first current interruption circuit 50 have a higher current capacity than the P-channel FETs 111A and 111B of the second current interruption circuit 100, charging and discharging with high currents is possible. 4. Effect

[0076] The present configuration can reduce the power consumption of the battery 20 and reduce the probability of failure of the second power interruption circuit 100. <Zweite Ausführungsform>

[0077] Typically, the current sensor 40, which is attached to the power line 35 of the battery 20, has a wide current measurement range. For example, if the battery 20 is to be used to start an engine, the starting current of the engine is approximately 1000 A, and the required measurement range of the current sensor 40 exceeds this value, e.g., approximately 1500 A. The current sensor 40 can measure high currents, and therefore the resistance value is low, approximately 100 µΩ, and therefore the current sensor 40 is not suitable for measuring small currents.

[0078] The second embodiment differs from the first embodiment in that the second embodiment uses the current limiting resistor 140 for current measurement. As shown in Fig. 13, both ends of the current limiting resistor 140 are connected to the management device 150 via a signal line Ls.

[0079] The management device 150 measures the current in the second current interruption circuit 100 based on the voltage at the two terminals Vr of the current limiting resistor 140.

[0080] In one example, the resistance of the current limiting resistor 140 is approximately 100 Ω, which is higher than the resistance of the current sensor 40 (approximately 100 μΩ), and a high voltage appears at two terminals Vr at the same current. Therefore, it is possible to very accurately measure the current to be discharged from the battery 20 (dark current when parked) with respect to the motor vehicle 1 while the second current interruption circuit 100 is closed.

[0081] By improving the current measurement accuracy, the estimation accuracy of SOC, etc. calculated based on the measured current value can be improved.

[0082] As in Fig. As shown in Figure 13, the current I flows through the current sensor 40 and the current limiting resistor 140 while the second current interruption circuit 100 is closed.

[0083] The management device 150 compares the measured current value I1 of the current sensor 40 with the measured current value I2 of the current limiting resistor 140 and determines an error ε of the measured current value I1, thereby correcting the error ε of the measured current value I1 of the current sensor 40. ε=I1−I2

[0084] By correcting the error ε while the first current interruption circuit 50 is closed (in this example in conditions other than parking), the current measurement accuracy of the current sensor 40 can be improved. <Andere Ausführungsformen>

[0085] The present invention is not limited to the embodiments explained with reference to the above description and the drawings, and the technical scope of the present invention also includes, for example, the following embodiments.

[0086] (1) The cell (repeatedly chargeable and dischargeable energy storage cell) 31 is not limited to a lithium-ion secondary battery cell, but may also be another non-aqueous electrolyte secondary battery cell. A capacitor may also be used instead of the secondary battery cell 31.

[0087] (2) In the first and second embodiments described above, the battery 20 is provided for use in a vehicle. The battery 20 is not limited to use in a vehicle, but can also be used for other purposes. In addition, the battery 20 can be used for a stationary application such as an energy storage device for absorbing fluctuations in a distributed power generation system or an uninterruptible power supply (UPS). When this technology is used for the UPS, during normal operation of the commercial power source, the second power interruption circuit 100 is closed (the first power interruption circuit 50 is open), and the trickle charge of the battery 20 with a low current below a predetermined value can be performed on a path along the second power interruption circuit 100. At abnormal times, such asDuring a power failure, such a measure is also possible in which the first power interruption circuit is closed (the second power interruption circuit 100 is open) and discharge of the battery 20 is performed with a high current of a predetermined value or higher on a path along the first power interruption circuit 50.

[0088] (3) In the first and second embodiments described above, when the battery 20 is used in the parked motor vehicle 10, the first power interrupt circuit 50 is open and the second power interrupt circuit 100 is closed. In other cases, for example, before the battery 20 is installed in the motor vehicle 10 (for example, during transportation of the battery) or when the battery 20 is detached from the motor vehicle 10, such a measure is possible in which the first power interrupt circuit 50 is open and the second power interrupt circuit 100 is closed. By such a measure, it is possible to reduce the standby power when the battery is at zero power. The coupling and decoupling to and from the motor vehicle 10 can be determined from the state of communication with the vehicle ECU 16.For example, if there is no communication at all with the vehicle ECU 16, it can be determined that it is located before being mounted on the motor vehicle 10. If there is no communication with the vehicle ECU 16 for a predetermined time or longer after starting communication with the vehicle ECU 16, it can be determined that the battery 20 has been removed from the motor vehicle 10.

[0089] (4) In the first and second embodiments described above, the second current interruption circuit 100 is closed when the vehicle 1 is parked. When the current I is less than a predetermined value, a measure may be taken to close the second current interruption circuit 100 and perform charging and discharging of the battery 20 on a path along the second current interruption circuit 100 even in cases other than parking. It is possible to determine whether the current I is less than a predetermined value based on the measured value of the current sensor 40.

[0090] (5) In the first and second embodiments described above, the current I of the second current limiting circuit 100 is limited by the current limiting resistor 140. The current limiting resistor 140 may be replaced by any device that can limit the current I.

[0091] (6) In the second embodiment described above, the measured current value I1 of the current sensor 40 is corrected with the measured current value I2 of the current-limiting resistor 140. The occurrence of a fault in the current sensor 40 can be determined by using the measured current value I2 of the current-limiting resistor 140. For example, if the difference between the two measured current values ​​(I1-I2) is greater than an allowable value, it can be determined that the current sensor 40 has caused a fault.

[0092] (7) In the first and second embodiments described above, it is assumed that the first switching circuit 60 is the two N-channel FETs 61A and 61B in back-to-back connection, and that the second switching circuit 110 is the two P-channel FETs 110A and 110B in back-to-back connection. The first switching circuit 60 and the second switching circuit 110 are not limited to the configuration described in the embodiments. Any other configuration can be used as long as it has a current capacity that satisfies the relationship in Fig. 9 is sufficient. The same applies to the first drive circuit 70 and the second drive circuit 120, which are also not limited to the configuration described in the embodiments. Any other configuration can be used as long as it has a power consumption that satisfies the relationship in Fig. 9 fulfilled.

[0093] Furthermore, in the above-described embodiments, the first current interruption circuit 50 and the second current interruption circuit 100 are arranged on a high side (positive electrode side) of the assembled battery 30, and the current sensor 40 is arranged on a low side (negative electrode side) of the assembled battery 30. A configuration is also possible in which the first current interruption circuit 50 and the second current interruption circuit 100 are arranged on a low side (negative electrode side) of the assembled battery 30, and the current sensor 40 is arranged on a high side (positive electrode side) of the assembled battery 30. Description of reference symbols 10 motor vehicle 20 Battery 31 cell 50 First power interruption circuit 60 First changeover switch 70 First drive circuit 100 Second power interruption circuit 110 Second changeover circuit 120 Second drive circuit 140 Current limiting resistor (current limiting device) 150 Management device (control unit) QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] WO 2011 / 158894

[0003]

Claims

[1] An energy storage device comprising: a cell; a first current interruption circuit arranged in a current path of the cell; a second current interruption circuit connected in parallel to the first current interruption circuit and having a lower current capacity and power consumption than the first current interruption circuit; and a control unit, where the second current interruption circuit includes a current limiting device, and when the current of the energy storage device is lower than a predetermined value, the control unit opens the first current interruption circuit and closes the second current interruption circuit. [2] The energy storage apparatus according to claim 1, wherein the current limiting device is a current limiting resistor, and the control unit measures the current based on the voltage at two terminals of the current limiting resistor. [3] The energy storage apparatus according to claim 2, comprising a current sensor that measures the current of the energy storage apparatus, wherein the control unit corrects a current measurement value of the current sensor based on a current measurement value of the current limiting device. [4] The energy storage apparatus according to claim 1 or 2, wherein when the current of the energy storage apparatus has the predetermined value or higher, the control unit closes the first current interruption circuit and opens the second current interruption circuit. [5] The energy storage apparatus according to claim 1 or 2, wherein the first power interruption circuit comprises: an N-channel field-effect transistor (FET) arranged on a high side of the cell; and a first drive circuit that drives the N-channel FET, and the second current interruption circuit comprises: a P-channel field-effect transistor (FET) connected in parallel with the N-channel FET; a second drive circuit that drives the P-channel FET; and the current limiting device. [6] The energy storage apparatus according to claim 1 or 2, which is for use in a vehicle, wherein while the vehicle is parked, the control unit opens the first power interruption circuit and closes the second power interruption circuit. [7] The energy storage apparatus according to claim 1 or 2, which is for use in a vehicle, wherein when the energy storage apparatus is not mounted on the vehicle or when the energy storage apparatus is detached from the vehicle, the control unit opens the first power interruption circuit and closes the second power interruption circuit.

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