Battery unit connection switching device and battery charging system

Abstract

To protect a charging infrastructure from malfunction of a relay.SOLUTION: A connection switching device for a battery unit includes: a connection switching unit that, when a first relay and a second relay are in an ON state and a third relay is in an OFF state, a connection switching unit connects a first battery unit and a second battery unit in parallel, and when the first relay and the second relay are in an OFF state and the third relay is in an ON state, this unit connects the first battery unit and the second battery unit in series; a first fuse and a second fuse connected in series to the first relay and the second relay, respectively; a cutoff unit connected in series to the third relay and capable of cutting off a current flowing through the third relay; and a detection unit that detects blowing of at least one of the first fuse and the second fuse. The cutoff unit cuts off the current flowing through the third relay when the detection unit detects the blowing of at least one of the first fuse and the second fuse.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a battery unit connection switching device and a battery charging system. [Background technology]

[0002] In order to improve the driving torque of electric vehicles (EVs) and shorten the battery charging time, the voltage of the motor drive batteries in EVs is becoming higher. For example, the charging time for a 60kWh battery is 20 minutes when charged at 400V and 400A, but 10 minutes when charged at 800V and 400A. However, much of the existing charging infrastructure, such as charging stations, is not compatible with 800V high-voltage charging.

[0003] Patent Documents 1 and 2 disclose charging devices that can switch the connection state of two 400V-class energy storage modules between series and parallel. For example, the charging device disclosed in Patent Document 1 includes one serialization relay RY2 and two parallelization relays RY1 and RY3. The energy storage modules are connected in series by turning on the serialization relay RY2 and turning off the parallelization relays RY1 and RY3, and the energy storage modules are connected in parallel by turning off the serialization relay RY2 and turning on the parallelization relays RY1 and RY3. When charging the energy storage modules with an 800V-class charging infrastructure, the energy storage modules are connected in series, and when charging the energy storage modules with a 400V-class charging infrastructure, the energy storage modules are connected in parallel. This makes it possible to support both 400V-class and 800V-class charging infrastructures. By connecting the energy storage modules in series when driving a load, it is possible to drive the load at 800V. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2019 / 082776 [Patent Document 2] U.S. Patent Publication No. 2019 / 160953 Summary of the Invention [Problem to be solved by the invention]

[0005] However, if a relay is switched due to a malfunction while the power storage module is being charged, the connection state of the power storage module may change, potentially causing damage to the charging infrastructure. [Means for solving the problem]

[0006] A battery unit connection switching device according to one embodiment of the present disclosure includes a connection switching unit that includes a first relay, a second relay, and a third relay, and that connects the first battery unit and the second battery unit in parallel when the first relay and the second relay are in an on state and the third relay is in an off state, and that connects the first battery unit and the second battery unit in series when the first relay and the second relay are in an off state and the third relay is in an on state; a first fuse and a second fuse connected in series to the first relay and the second relay, respectively; an interrupter connected in series to the third relay and capable of interrupting a current flowing through the third relay; and a detection unit that detects the blowing of at least one of the first fuse and the second fuse, and the interrupter interrupts the current flowing through the third relay when the detection unit detects the blowing of at least one of the first fuse and the second fuse.

[0007] The present disclosure can be realized not only as a battery unit connection switching device having the above-described characteristic configuration, but also as a battery unit connection switching method including steps of characteristic processing in the battery unit connection switching device. The present disclosure can be realized as a computer program that causes a computer to function as the battery unit connection switching device, as a semiconductor integrated circuit that is part or all of the battery unit connection switching device, or as a battery charging system that includes the battery unit connection switching device. [Effects of the Invention]

[0008] According to the present disclosure, even if the connection state of the battery unit changes due to a malfunction of the relay, the charging infrastructure can be protected. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing an example of the overall configuration of a vehicle charging system according to the first embodiment. [Figure 2] FIG. 2 is a circuit diagram showing an example of the configuration of the battery charging system according to the first embodiment. [Figure 3] FIG. 3 is a circuit diagram showing an example of the configuration of the connection switching device according to the first embodiment. [Figure 4] FIG. 4 is a circuit diagram for explaining the occurrence of an overcurrent in a connection switching device of the comparative example. [Figure 5] FIG. 5 is a circuit diagram for explaining the current flow when the fuse for overcurrent protection is blown in the connection switching device of the comparative example. [Figure 6] FIG. 6 is a circuit diagram for explaining the operation when the third relay of the connection switching device according to the first embodiment malfunctions. [Figure 7] FIG. 7 is a circuit diagram showing an example of the configuration of a connection switching device according to the second embodiment. [Figure 8] FIG. 8 is a circuit diagram showing an example of the configuration of a connection switching device according to the third embodiment. [Figure 9] FIG. 9 is a circuit diagram showing an example of the configuration of a connection switching device according to the fourth embodiment. [Figure 10] FIG. 10 is a circuit diagram showing an example of the configuration of a connection switching device according to the fifth embodiment. [Figure 11] FIG. 11 is a block diagram showing an example of the hardware configuration of a control circuit according to the fifth embodiment. [Figure 12] FIG. 12 is a flowchart showing an example of a control process performed by the control circuit according to the fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0010] <Summary of Embodiments of the Present Disclosure> The following provides an outline of embodiments of the present disclosure.

[0011] (1) The battery unit connection switching device of this embodiment includes a connection switching unit that includes a first relay, a second relay, and a third relay, and that connects the first battery unit and the second battery unit in parallel when the first relay and the second relay are in an on state and the third relay is in an off state, and that connects the first battery unit and the second battery unit in series when the first relay and the second relay are in an off state and the third relay is in an on state; a first fuse and a second fuse connected in series to the first relay and the second relay, respectively; a cutoff unit connected in series to the third relay and capable of cutting off the current flowing to the third relay; and a detection unit that detects the blowing of at least one of the first fuse and the second fuse, and the cutoff unit cuts off the current flowing to the third relay when the detection unit detects the blowing of at least one of the first fuse and the second fuse. As a result, if the third relay malfunctions and turns on while the first battery unit and the second battery unit are being charged when the first battery unit and the second battery unit are connected in parallel, an overcurrent flows through the first fuse and the second fuse, causing at least one of the first fuse and the second fuse to melt. When at least one of the first fuse and the second fuse melts, the current flowing through the third relay is cut off by the circuit breaker, thereby protecting the charging infrastructure from an overcurrent.

[0012] (2) In the above (1), the interrupter may be a pyro-fuse. When at least one of the first fuse and the second fuse is blown, the pyro-fuse detonates to interrupt the current flowing through the third relay.

[0013] (3) In the above (1), the interrupter may be a semiconductor relay. With this, when at least one of the first fuse and the second fuse is blown, the semiconductor relay is turned off, and the current flowing through the third relay can be interrupted.

[0014] (4) In the above (3), the semiconductor relay may include a body diode, and the semiconductor relay may be connected in series with the third relay so that the body diode does not pass a first direction current discharged from at least one of the first battery unit and the second battery unit, but passes a second direction current opposite to the first direction. This makes it possible to prevent current from flowing to the third relay through the body diode when the semiconductor relay is turned off.

[0015] (5) In the above (1), the interrupter may be a series-connected circuit of a first semiconductor relay and a second semiconductor relay, the first semiconductor relay including a first body diode, and the second semiconductor relay including a second body diode oriented opposite to the first body diode. This makes it possible to prevent current from flowing to the third relay through either the first body diode or the second body diode when the first semiconductor relay and the second semiconductor relay are turned off.

[0016] (6) In any one of (1) to (5) above, the detection unit may include a photocoupler connected in parallel with the first fuse or the second fuse, an output terminal of the photocoupler may be connected to the cutoff unit, and the cutoff unit may cut off the current flowing through the third relay when receiving an output signal from the photocoupler. This allows the photocoupler to quickly detect the blowout of the first fuse or the second fuse and cut off the current flowing through the third relay.

[0017] (7) In any one of the above (1) to (5), the detection unit may include a current sensor that detects a current flowing through the first battery unit or the second battery unit, and a control unit that outputs a control signal for controlling the interrupter based on the detection result of the current sensor. When the first fuse and the second fuse melt, a current flows through the first battery unit and the second battery unit. Therefore, the melting of the first fuse or the second fuse can be detected by the current sensor.

[0018] (8) A battery charging system according to this embodiment includes a first battery unit, a second battery unit, and a connection switching device that switches a connection between the first battery unit and the second battery unit. The connection switching device includes a connection switching unit that includes a first relay, a second relay, and a third relay, and that connects the first battery unit and the second battery unit in parallel when the first relay and the second relay are in an on state and the third relay is in an off state, and that connects the first battery unit and the second battery unit in series when the first relay and the second relay are in an off state and the third relay is in an on state; a first fuse and a second fuse connected in series to the first relay and the second relay, respectively; an interrupter connected in series to the third relay and capable of interrupting a current flowing through the third relay; and a detection unit that detects the blowing of at least one of the first fuse and the second fuse, and the interrupter interrupts the current flowing through the third relay when the detection unit detects the blowing of at least one of the first fuse and the second fuse. As a result, if the third relay malfunctions and turns on while the first battery unit and the second battery unit are being charged when the first battery unit and the second battery unit are connected in parallel, an overcurrent flows through the first fuse and the second fuse, causing at least one of the first fuse and the second fuse to melt. When at least one of the first fuse and the second fuse melts, the current flowing through the third relay is cut off by the circuit breaker, thereby protecting the charging infrastructure from an overcurrent.

[0019] <Details of the embodiment of the present disclosure> DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. At least some of the following preferred embodiments may be combined in any desired manner.

[0020] [1. First embodiment] [1-1. Vehicle charging system] 1 is a diagram showing an example of the overall configuration of a vehicle charging system according to Embodiment 1. The vehicle charging system 10 includes an electric vehicle 20 such as an EV or a plug-in hybrid vehicle, and a charging device 30.

[0021] The electric vehicle 20 includes a high-voltage load 500 including a motor for driving the vehicle, and a battery charging system 100 for charging a first battery unit 200A and a second battery unit 200B for driving the high-voltage load. The electric vehicle 20 further includes an inlet 300 and an on-board control device 400. The first battery unit 200A and the second battery unit 200B are 400V-class secondary batteries, such as lithium-ion batteries. Note that, hereinafter, the "first battery unit 200A" and the "second battery unit 200B" will also be collectively referred to as "battery units 200A, 200B."

[0022] The charging device 30 is a DC charging station for the electric vehicle 20. The charging device 30 converts AC power supplied from a system power supply (for example, a commercial AC power supply) into DC power for charging the battery units 200A, 200B of the electric vehicle 20. The charging device 30 includes a connector 30a. The connector 30a is attachable to and detachable from the inlet 300. The charging device 30 can output DC power from the connector 30a. The charging device 30 may be a 400V charging device capable of outputting 400V DC power, or may be an 800V charging device capable of outputting 800V DC power.

[0023] The inlet 300 is an input port for charging power to the battery units 200A, 200B0, and is connected to the battery units 200A, 200B by power lines. When the connector 30a is connected to the inlet 300, the charging device 30 charges the battery units 200A, 200B0 of the electric vehicle 20.

[0024] The inlet 300 is connected to the on-board control device 400 via a communication line (not shown). When the connector 30a is connected to the inlet 300, the on-board control device 400 can communicate with the charging device 30 using a specific communication protocol. For example, the on-board control device 400 can communicate using a Controller Area Network (CAN). In another example, the on-board control device 400 can communicate using Ethernet (registered trademark).

[0025] The on-board controller 400 is connected to the battery charging system 100 via a communication line. The on-board controller 400 transmits control signals to the battery charging system 100 to control the operation of the battery charging system 100.

[0026] [1-2. Battery charging system] FIG. 2 is a circuit diagram showing an example of the configuration of the battery charging system according to the first embodiment.

[0027] The battery charging system 100 includes a DC bus including a positive power line 150P and a negative power line 150N. The power lines 150P and 150N are connected to a high-voltage load 500. DC power output from the battery units 200A and 200B is supplied to the high-voltage load 500 through the power lines 150P and 150N. The high-voltage load 500 includes a resistance component 501 and a capacitance component 502.

[0028] Each of the power lines 150P, 150N branches off midway, and the branched ends are connected to the inlet 300. A DC relay 151A is provided on the positive power line extending from the inlet 300 to the branch point, and a DC relay 151B is provided on the negative power line. The DC relays 151A, 151B are relays that switch between connection and disconnection between the inlet 300 and the battery units 200A, 200B. The DC relays 151A, 151B are controlled by the on-board control device 400 (see FIG. 1), and are turned on when the battery units 200A, 200B are being charged, and are turned off when not being charged.

[0029] Main relays 152A, 152B are provided on the power lines 150P, 150N, respectively. Furthermore, a series circuit of a main relay 152C and a resistor 154 is provided on the power line 150N in parallel with the main relay 152B. The main relays 152A, 152B, 152C are relays that switch between connection and disconnection between the battery units 200A, 200B and the high-voltage load 500. The main relays 152A, 152B, 152C are controlled by the on-board control device 400 (see FIG. 1), and are turned on when the electric vehicle 20 is in operation and turned off when the electric vehicle 20 is not in operation.

[0030] The DC relays 151A and 151B and the main relays 152A, 152B, and 152C are, for example, mechanical relays, but at least one of the DC relays 151A and 151B and the main relays 152A, 152B, and 152C may be a semiconductor relay such as a power MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor).

[0031] The battery charging system 100 includes a voltage sensor 155 that detects the voltage between the power lines 150P and 150N. The detection result of the voltage sensor 155 is provided to the on-board controller 400. The on-board controller 400 uses the detection result of the voltage sensor 155 to control the battery charging system 100.

[0032] The power lines 150P and 150N are connected to the connection switching device 110. The connection switching device 110 switches between a series connection and a parallel connection of the battery units 200A and 200B.

[0033] [1-3. Connection switching device] FIG. 3 is a circuit diagram showing an example of the configuration of the connection switching device according to the first embodiment.

[0034] The power line 150P is connected to a connection point 157P of the power lines 156A and 156B. The positive and negative electrodes of the first battery unit 200A are connected to the power line 156A. The positive and negative electrodes of the second battery unit 200B are connected to the power line 156B. The power lines 156A and 156B are connected at a connection point 157N on the negative side of the first battery unit 200A and the negative side of the second battery unit 200B. The power line 150N is connected to the connection point 157N.

[0035] A first relay 111A is provided between the negative electrode of the first battery unit 200A and the connection point 157N. A second relay 111B is provided between the connection point 157P and the positive electrode of the second battery unit 200B. The first relay 111A and the second relay 111B are controlled by the on-board control device 400.

[0036] An intermediate point 157A between the negative electrode of the first battery unit 200A and the first relay 111A is connected to an intermediate point 157B between the second relay 111B and the positive electrode of the second battery unit 200B by a power line 156C. A third relay 111C is provided on the power line 156C. The third relay 111C is controlled by the on-board controller 400.

[0037] When the first relay 111A and the second relay 111B are in an ON state and the third relay 111C is in an OFF state, the first battery unit 200A and the second battery unit 200B are connected in parallel. When the battery units 200A, 200B are charged by the charging device 30, the on-board control device 400 controls the first relay 111A, the second relay 111B, and the third relay 111C to connect the first battery unit 200A and the second battery unit 200B in parallel.

[0038] When the first relay 111A and the second relay 111B are in the OFF state and the third relay 111C is in the ON state, the first battery unit 200A and the second battery unit 200B are connected in series. When driving the high-voltage load 500, the on-board control device 400 controls the first relay 111A, the second relay 111B, and the third relay 111C to connect the first battery unit 200A and the second battery unit 200B in series.

[0039] The first relay 111A, the second relay 111B, and the third relay 111C constitute a connection switching unit 111s. The connection switching unit 111s switches between a series connection and a parallel connection of the first battery unit 200A and the second battery unit 200B.

[0040] A current sensor 140A is provided between the negative electrode of the first battery unit 200A and the intermediate point 157A. A current sensor 140B is provided between the positive electrode of the second battery unit 200B and the intermediate point 157B. The current sensor 140A detects the current flowing through the first battery unit 200A, and the current sensor 140B detects the current flowing through the second battery unit 200B. The detection results of the current sensors 140A and 140B are provided to the on-board controller 400. The on-board controller 400 uses the detection results of the current sensors 140A and 140B to control the battery charging system 100.

[0041] A first fuse 112A is provided between the first relay 111A and the connection point 157N. A second fuse 112B is provided between the connection point 157P and the second relay 111B. The first fuse 112A and the second fuse 112B are fuses for overcurrent protection that melt when an overcurrent flows.

[0042] A photocoupler 120A and a resistor 122A, which are connected in series, are connected in parallel to the first fuse 112A. The photocoupler 120A includes an LED (Light Emitting Diode) 121A, which is a light-emitting element, and a phototransistor 123A, which is a light-receiving element. The phototransistor 123A is normally in an off state and turns on when the LED 121A emits light. The output of the phototransistor 123A is 0 (V) in the off state and Vcc (V) in the on state.

[0043] A photocoupler 120B and a resistor 122B, which are connected in series, are connected in parallel to the second fuse 112B. The photocoupler 120B includes an LED 121B, which is a light-emitting element, and a phototransistor 123B, which is a light-receiving element. The phototransistor 123B is normally in an off state and turns on when the LED 121B emits light. The output of the phototransistor 123B is 0 (V) in the off state and Vcc (V) in the on state.

[0044] In the power line 156C, a pyrofuse 130 is connected in series to the third relay 111C. When a predetermined voltage signal is applied, the pyrofuse 130 explodes and cuts off the conductive path. The pyrofuse 130 is an example of a cutoff unit that cuts off the current flowing through the third relay 111C.

[0045] Photocouplers 120A and 120B configure detection unit 125. Detection unit 125 detects the blowing of at least one of first fuse 112A and second fuse 112B. Output terminals of photocouplers 120A and 120B are connected to pyro-fuse .

[0046] [1-4. Operation of the connection switching device] First, the occurrence of an overcurrent will be described using a connection switching device 110S of a comparative example, which is obtained by removing the pyro-fuse 130 and the detection unit 125 from the connection switching device 110 of this embodiment. Fig. 4 is a circuit diagram for explaining the occurrence of an overcurrent in the connection switching device of the comparative example.

[0047] While the battery units 200A and 200B are being charged, the first relay 111A and the second relay 111B are in the ON state, and the third relay 111C is in the OFF state. That is, the first battery unit 200A and the second battery unit 200B are connected in parallel.

[0048] Consider a case where third relay 111C malfunctions and turns on when battery units 200A, 200B are connected in parallel. The malfunction of third relay 111C can be caused by software malfunction, vibration, or the like. When third relay 111C turns on, overcurrent (1), which is a direct current supplied from charging device 30, flows through a path extending from connection point 157P of power line 156B to midpoint 157B, power line 156C, and from midpoint 157A of power line 156A to connection point 157N. Furthermore, overcurrent (2) discharged from the first battery unit 200A flows through the power line 156A from the positive terminal of the first battery unit 200A to the connection point 157P, the power line 156B from the connection point 157P to the midpoint 157B, the power line 156C, and the power line 156A from the midpoint 157A to the negative terminal of the first battery unit 200A. Similarly, overcurrent (2) discharged from the second battery unit 200B flows through the power line 156B from the positive terminal of the second battery unit 200B to the midpoint 157B, the power line 156C, the power line 156A from the midpoint 157A to the connection point 157N, and the power line 156B from the connection point 157N to the negative terminal of the second battery unit 200B.

[0049] 5 is a circuit diagram illustrating the current flow when the fuse for overcurrent protection blows in the connection switching device of the comparative example. As described above, when overcurrents (1) and (2) occur, first fuse 112A and second fuse 112B blow. This causes overcurrent (3) due to the discharge of battery units 200A and 200B to flow through a path extending from connection point 157N of power line 156B to midpoint 157B, power line 156C, and from midpoint 157A of power line 156A to connection point 157P. Such overcurrent (3) may flow into charging device 30, potentially damaging charging device 30.

[0050] Next, with reference to FIG. 3, the overcurrent protection operation of the connection switching device 110 according to this embodiment will be described. When the battery units 200A, 200B are connected in parallel, if the third relay 111C malfunctions and enters the ON state, overcurrents (1) and (2) occur as described above. When the first fuse 112A melts, a current flows through the LED 121A, causing the LED 121A to emit light. This turns on the phototransistor 123A, which then outputs a detection signal with a voltage value of Vcc. Similarly, when the second fuse 112AB melts, a current flows through the LED 121B, causing the LED 121B to emit light. This turns on the phototransistor 123B, causing the phototransistor 123B to emit light. This turns on the phototransistor 123B, causing the phototransistor 123B to output a detection signal with a voltage value of Vcc.

[0051] When a detection signal is output from at least one of the photocouplers 120A and 120B, the pyro-fuse 130 is detonated by the detection signal.

[0052] Fig. 6 is a circuit diagram for explaining the operation when the third relay 111C of the connection switching device according to the first embodiment malfunctions. Note that, for simplification, the detection unit 125 is omitted from Fig. 6. When the pyro-fuse 130 explodes, the power line 156C is cut off and the current flowing through the third relay 111C is interrupted. Therefore, all paths of the overcurrent in the connection switching device 110 are cut off, and the charging device 30 can be protected from the overcurrent.

[0053] [2. Second Embodiment] 7 is a circuit diagram showing an example of the configuration of a connection switching device according to the second embodiment. A connection switching device 110A according to the second embodiment includes a semiconductor relay 130A as a cutoff unit instead of the pyro-fuse 130. Other configurations of the connection switching device 110A according to the second embodiment are the same as those of the connection switching device 110 according to the first embodiment, and therefore the same components are denoted by the same reference numerals and description thereof will be omitted.

[0054] The semiconductor relay 130A is, for example, a power MOSFET. The semiconductor relay 130A includes a body diode 131. The body diode 131 is arranged in the opposite direction to the flow of the overcurrent (3). In other words, the semiconductor relay 130A is connected in series with the third relay 111C so that the body diode 131 does not pass current in a first direction X1, which is discharged from the second battery unit 200B, but passes current in a second direction X2 opposite to the first direction X1.

[0055] The gate terminal of the semiconductor relay 130A is connected to the output terminals of the photocouplers 120A and 120B.

[0056] The semiconductor relay 130A is normally in an ON state. Therefore, when the first relay 111A and the second relay 111B are in an OFF state and the third relay 111C is in an ON state, the battery units 200A and 200B are connected in series.

[0057] When the first fuse 112A and the second fuse 112B blow due to an overcurrent, a detection signal is output from the photocouplers 120A and 120B. The detection signal is applied to the gate terminal of the semiconductor relay 130A, causing the semiconductor relay 130A to transition from an ON state to an OFF state. This disconnects the power line 156C. Furthermore, because the body diode 131 is arranged in the X2 direction, the overcurrent in the X1 direction does not pass through the body diode 131. This blocks the current flowing through the third relay 111C.

[0058] 3. Third Embodiment 8 is a circuit diagram showing an example of the configuration of a connection switching device according to the third embodiment. A connection switching device 110B according to the third embodiment includes a cutoff unit 130B configured by a first semiconductor relay 133A and a second semiconductor relay 133B instead of the pyro-fuse 130. Other configurations of the connection switching device 110B according to the third embodiment are similar to those of the connection switching device 110 according to the first embodiment, and therefore the same components are designated by the same reference numerals and description thereof will be omitted.

[0059] The first semiconductor relay 133A and the second semiconductor relay 133B are connected in series with each other. The first semiconductor relay 133A and the second semiconductor relay 133B are, for example, power MOSFETs. The first semiconductor relay 133A includes a first body diode 134A, and the second semiconductor relay 133B includes a second body diode 134B. The first body diode 134A is oriented so as not to allow current to flow in a first direction X1 but to allow current to flow in a second direction X2 opposite to the first direction X1. The second body diode 134B is oriented so as not to allow current to flow in the second direction X2 but to allow current to flow in the first direction X1. In other words, the first body diode 134A and the second body diode 134B are oriented in opposite directions to each other.

[0060] The gate terminals of the first semiconductor relay 133A and the second semiconductor relay 133B are connected to the output terminals of the photocouplers 120A and 120B, respectively.

[0061] When the first fuse 112A and the second fuse 112B blow due to an overcurrent, a detection signal is output from the photocouplers 120A and 120B. The detection signal is applied to the gate terminals of the first semiconductor relay 133A and the second semiconductor relay 133B, respectively, causing the first semiconductor relay 133A and the second semiconductor relay 133B to transition from an ON state to an OFF state. This disconnects the power line 156C. Furthermore, because the first body diode 134A and the second body diode are arranged in opposite directions, the passage of both current in the X1 direction and current in the X2 direction is blocked. This blocks the current flowing through the third relay 111C.

[0062] [4. Fourth Embodiment] 9 is a circuit diagram showing an example of the configuration of a connection switching device according to the fourth embodiment. A connection switching device 110C according to the fourth embodiment includes a detection unit 125C including current sensors 140A and 140B and comparators 420A and 420B, instead of the detection unit 125 including photocouplers 120A and 120B. Other configurations of the connection switching device 110C according to the fourth embodiment are similar to those of the connection switching device 110 according to the first embodiment, and therefore the same components are denoted by the same reference numerals and description thereof will be omitted.

[0063] The comparator 420A includes a first input terminal, a second input terminal, and an output terminal. A signal line extending from the output terminal of the current sensor 140A is connected to the first input terminal of the comparator 420A. A reference threshold voltage Vth is input to the second input terminal of the comparator 420A. The output terminal of the comparator 420A is connected to the pyrofuse 130. Note that in this embodiment, the connection switching device 110C may include, instead of the pyrofuse 130, the semiconductor relay 130A in the second embodiment, or the cutoff unit 130B including the first semiconductor relay 133A and the second semiconductor relay 133B in the third embodiment.

[0064] The comparator 420B includes a first input terminal, a second input terminal, and an output terminal. A signal line extending from the output terminal of the current sensor 140B is connected to the first input terminal of the comparator 420B. A reference threshold voltage Vth is input to the second input terminal of the comparator 420B. The output terminal of the comparator 420B is connected to the pyrofuse 130.

[0065] Comparators 420A and 420B are an example of a control unit. Comparator 420A outputs a control signal for controlling pyro-fuse 130 based on the detection result of current sensor 140A. Specifically, current sensor 140A outputs a voltage signal whose value corresponds to the detected current value. Comparator 420A compares the output voltage of current sensor 140A with a threshold voltage Vth, and outputs a control signal according to the comparison result. In other words, comparator 420A outputs a control signal when the output voltage of current sensor 140A exceeds threshold voltage Vth. Comparator 420B operates in a similar manner, so a description thereof will be omitted.

[0066] The threshold voltage Vth is a value for determining whether the current detected by the current sensors 140A and 140B is an overcurrent. That is, the threshold voltage Vth is set to a value corresponding to the current value of the overcurrent (3).

[0067] When first fuse 112A and second fuse 112B blow due to an overcurrent, overcurrent (3) caused by the discharge of battery units 200A and 200B flows through a path extending from connection point 157N of power line 156B to midpoint 157B, power line 156C, and from midpoint 157A of power line 156A to connection point 157P. Current sensors 140A and 140B detect the current value of overcurrent (3) and output a voltage signal corresponding to the detected current value.

[0068] Comparators 420A and 420B compare the output voltages from current sensors 140A and 140B with threshold voltage Vth. When overcurrent (3) occurs, the output voltages of current sensors 140A and 140B exceed threshold voltage Vth. As a result, comparators 420A and 420B output a control signal. The control signal detonates pyrotechnic fuse 130, cutting off the current flowing through third relay 111C.

[0069] [5. Fifth Embodiment] 10 is a circuit diagram showing an example of the configuration of a connection switching device according to the fifth embodiment. A connection switching device 110D according to the fifth embodiment includes a detection unit 125D including current sensors 140A and 140B and a control circuit 520, instead of the detection unit 125 including photocouplers 120A and 120B. Other configurations of the connection switching device 110D according to the fifth embodiment are similar to those of the connection switching device 110 according to the first embodiment, and therefore the same components are denoted by the same reference numerals and description thereof will be omitted.

[0070] Signal lines extending from the output terminals of current sensors 140A and 140B are connected to control circuit 520. Control circuit 520 is connected to pyrofuse 130 via the signal lines. Note that in this embodiment, connection switching device 110D may include, instead of pyrofuse 130, semiconductor relay 130A in the second embodiment, or breaker unit 130B including first semiconductor relay 133A and second semiconductor relay 133B in the third embodiment.

[0071] The control circuit 520 is an example of a control unit. The control circuit 520 outputs a control signal for controlling the pyro-fuse 130 based on the detection results of at least one of the current sensors 140A and 140B. Specifically, the current sensors 140A and 140B output detection signals indicating the detected current values. The control circuit 520 compares the first current value A1 and the second current value A2 detected by the current sensors 140A and 140B, respectively, with a threshold value Th, and outputs a control signal according to the comparison result. That is, the control circuit 520 outputs a control signal when the first current value A1 detected by the current sensor 140A exceeds the threshold value Th, or when the second current value A2 detected by the current sensor 140B exceeds the threshold value Th.

[0072] The threshold voltage Th is a value for determining whether or not the current detected by the current sensors 140A and 140B is an overcurrent. That is, the threshold voltage Th is set to a value corresponding to the current value of the overcurrent (3).

[0073] FIG. 11 is a block diagram showing an example of the hardware configuration of a control circuit according to the fifth embodiment.

[0074] The control circuit 520 includes a processor 521 , a non-volatile memory 522 , a volatile memory 523 , and an input / output interface (I / O) 524 .

[0075] The volatile memory 523 is a volatile memory such as an SRAM (Static Random Access Memory) or a DRAM (Dynamic Random Access Memory). The nonvolatile memory 522 is a nonvolatile memory such as a flash memory, a hard disk, or a ROM (Read Only Memory). The nonvolatile memory 522 stores a control program 525, which is a computer program, and data used to execute the control program 525. Each function of the control circuit 520 is realized by the processor 521 executing the control program 525. The control program 525 can be stored in a recording medium such as a flash memory, a ROM, or a CD-ROM.

[0076] The processor 521 is, for example, a CPU (Central Processing Unit). However, the processor 521 is not limited to a CPU. The processor 521 may be a GPU (Graphics Processing Unit). In a specific example, the processor 521 is a multi-core GPU. The processor 521 may be, for example, an ASIC (Application Specific Integrated Circuit) or a programmable logic device such as a gate array or FPGA (Field Programmable Gate Array). In this case, the ASIC or programmable logic device is configured to be able to execute the same processing as the control program 525. The control circuit 520 is, for example, a microcomputer made up of a single-chip semiconductor component.

[0077] The I / O 524 inputs and outputs signals. The output terminals of the current sensors 140A and 140B are connected to the I / O 524 via signal lines. The I / O 524 is also connected to the input terminal of the pyrofuse 130 via a signal line.

[0078] While the battery units 200A, 200B are being charged, the first relay 111A and the second relay 111B are in the ON state, and the third relay 111C is in the OFF state. That is, the first battery unit 200A and the second battery unit 200B are connected in parallel. In this state, the processor 521 executes the control program 525. When the processor 521 executes the control program 525, the control circuit 520 executes the following control processing. FIG. 12 is a flowchart showing an example of the control processing by the control circuit according to the fifth embodiment.

[0079] The processor 521 receives the first current value A1 and the second current value A2 output from the current sensors 140A and 140B, respectively (step S101).

[0080] Next, processor 521 compares first current value A1 with threshold value Th and compares second current value A2 with threshold value Th (step S102). If first current value A1 is equal to or less than threshold value Th and second current value A2 is equal to or less than threshold value Th (NO in step S102), processor 521 returns to step S101.

[0081] If first current value A1 exceeds threshold value Th or second current value A2 exceeds threshold value Th (YES in step S102), processor 521 outputs a control signal to pyrofuse 130 (step S103). The control signal detonates pyrofuse 130, and the current flowing through third relay 111C is interrupted. This ends the control process.

[0082] [6. Supplementary Notes] The embodiments disclosed herein are illustrative in all respects and are not restrictive. The scope of the present invention is defined by the claims rather than the above-described embodiments, and includes meanings equivalent to the claims and all modifications within the scope thereof. [Explanation of symbols]

[0083] 10 Vehicle charging system 20 Electric vehicles 30 Charging device 30a connector 100 Battery Charging System 110, 110A, 110B, 110C, 110D, 110S connection switching device 111A First Relay 111B Second Relay 111C 3rd relay 111s connection switch 112A First Fuse 112B Second Fuse 120A, 120B photocoupler 121A LED 122A,122B resistance 123A, 123B phototransistor 125, 125C, 125D detection unit 130 Pyro Fuse 130A solid state relay 130B Breaker 131 Body diode 133A 1st Solid State Relay 133B Second semiconductor relay 134A First body diode 134B Second body diode 140A, 140B current sensor 150P,150N power line 151A, 151B Relay 152A, 152B, 152C Main relay 154 Resistance 155 Voltage Sensor 156A,156B,156C power line 157A,157B midpoint 157P, 157N connection point 200A 1st battery unit 200B Second Battery Unit 300 Inlet 400 In-vehicle control device 420A, 420B Comparators 500 High Pressure Load 501 Resistance component 502 Capacitive Component 520 Control circuit 521 processor 522 Non-volatile memory 523 Volatile Memory 524 Input / Output Interface (I / O) 525 Control Program X1 1st direction X2 2nd direction

Claims

1. a connection switching unit including a first relay, a second relay, and a third relay, which connects the first battery unit and the second battery unit in parallel when the first relay and the second relay are in an on state and the third relay is in an off state, and which connects the first battery unit and the second battery unit in series when the first relay and the second relay are in an off state and the third relay is in an on state; a first fuse and a second fuse connected in series to the first relay and the second relay, respectively; a cutoff unit connected in series to the third relay and capable of cutting off a current flowing through the third relay; a detection unit that detects blowout of at least one of the first fuse and the second fuse; Equipped with the interrupter interrupts the current flowing through the third relay when the detector detects that at least one of the first fuse and the second fuse has blown. Battery unit connection switching device.

2. The interrupter is a pyro fuse. The battery unit connection switching device according to claim 1 .

3. The interrupter is a semiconductor relay. The battery unit connection switching device according to claim 1 .

4. the semiconductor relay includes a body diode; the semiconductor relay is connected in series with the third relay so that the body diode does not pass a current in a first direction discharged from at least one of the first battery unit and the second battery unit, but passes a current in a second direction opposite to the first direction; The battery unit connection switching device according to claim 3 .

5. the interrupter includes a first semiconductor relay and a second semiconductor relay connected in series, the first semiconductor relay includes a first body diode; the second semiconductor relay includes a second body diode oriented opposite to the first body diode; The battery unit connection switching device according to claim 1 .

6. the detection unit includes a photocoupler connected in parallel with the first fuse or the second fuse, an output terminal of the photocoupler is connected to the interrupter; The cutoff unit cuts off the current flowing through the third relay when receiving an output signal from the photocoupler. The battery unit connection switching device according to any one of claims 1 to 5.

7. The detection unit a current sensor that detects a current flowing through the first battery unit or the second battery unit; a control unit that outputs a control signal for controlling the interrupter based on a detection result of the current sensor; Including, The battery unit connection switching device according to any one of claims 1 to 5.

8. a first battery unit; a second battery unit; a connection switching device that switches the connection between the first battery unit and the second battery unit; Equipped with The connection switching device a connection switching unit including a first relay, a second relay, and a third relay, which connects the first battery unit and the second battery unit in parallel when the first relay and the second relay are in an on state and the third relay is in an off state, and which connects the first battery unit and the second battery unit in series when the first relay and the second relay are in an off state and the third relay is in an on state; a first fuse and a second fuse connected in series to the first relay and the second relay, respectively; a cutoff unit connected in series to the third relay and capable of cutting off a current flowing through the third relay; a detection unit that detects blowout of at least one of the first fuse and the second fuse; Including, the interrupter interrupts the current flowing through the third relay when the detector detects that at least one of the first fuse and the second fuse has blown. Battery charging system.

Images