Power distribution device

Abstract

To provide a power distribution device which can switch between series connection and parallel connection of a battery and can more appropriately correspond to both an external short circuit and a battery short circuit.SOLUTION: A power distribution device includes: first to seventh lines L1 to L7; a first switch SW1 for controlling conduction and interruption in the third line L3; a second switch SW2 for controlling conduction and interruption in the fourth line L4; a third switch SW3 for controlling conduction and interruption in the fifth line L5; a control part 63 for controlling a conduction state and an interruption state of the first to third switches SW1 to SW3; a first fuse F1 provided in the third line L3; a second fuse F2 which is provided in the fourth line L4 and whose conduction capacity is lower than the first fuse F1; and a third fuse F3 which is provided in the fifth line L5 and whose conduction capacity is lower than the first fuse F1.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to power distribution devices. [Background technology]

[0002] In recent years, with consideration for the environment, electric vehicles equipped with high-voltage batteries such as EVs (Electric Vehicles) and PHEVs (Plug-in Hybrid Electric Vehicles) have appeared. The voltage of these electric vehicles is increasing year by year, for example from about 400V to about 800V. As the voltage of electric vehicles increases, the standard voltage of chargers for electric vehicles is also increasing, making them compatible with vehicles equipped with high-voltage batteries. However, since chargers with higher standards require a lot of power, they are difficult to install in areas with poor power conditions, and it is also difficult to replace all currently installed chargers so that they can handle a voltage of, for example, 800V.

[0003] In response, a power distribution device has been proposed that allows secondary batteries mounted on electric vehicles to be connected in series or in parallel (see, for example, Patent Document 1). With this power distribution device, by switching to a parallel connection during charging, the voltage during charging can be made lower than when the batteries are connected in series. Therefore, a high-voltage electric vehicle can be charged even with a low voltage. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-64408 Summary of the Invention [Problem to be solved by the invention]

[0005] Here, the power distribution device described in Patent Document 1 is required to deal with external short circuits in both the load side and the charger side, and also needs to switch between series and parallel connections, so that it needs to deal with external short circuits in both connection states. The power distribution device described in Patent Document 1 also needs to protect against battery short circuits that can occur when a failure occurs in the switch that switches between series and parallel connections. In particular, the power distribution device described in Patent Document 1 is configured to deal with switch failures by providing fuses for each switch.

[0006] However, in the power distribution device described in Patent Document 1, a path is formed to pass through all secondary batteries whether they are connected in series or in parallel, so the fuse must be selected taking into consideration the maximum current. For example, if the current is 300A in series and 100A in parallel, a fuse capable of handling 300A is required. Therefore, if an abnormality occurs when connected in parallel, the time to withstand the abnormal condition will be long, and it is difficult to say that the device is dealing with the problem appropriately.

[0007] Therefore, an object of the present disclosure is to provide a power distribution device that is capable of switching between series connection and parallel connection of batteries and can more appropriately respond to both external short circuits and battery short circuits. [Means for solving the problem]

[0008] In order to solve the above problems, a power distribution device according to an embodiment of the present disclosure includes a first battery positive terminal and a first battery negative terminal connected to a positive electrode and a negative electrode of a first battery, respectively, a second battery positive terminal and a second battery negative terminal connected to a positive electrode and a negative electrode of a second battery, respectively, a charger positive terminal and a charger negative terminal connected to a positive electrode and a negative electrode of a charger, respectively, a load positive terminal and a load negative terminal connected to a positive electrode and a negative electrode of a load, respectively, a first line connecting the first battery positive terminal and the charger positive terminal, a second line connecting the second battery negative terminal and the charger negative terminal, a third line connecting the second battery positive terminal and the first battery negative terminal, a first switch controlling conduction and cutoff in the third line, a fourth line connecting the second battery positive terminal and the first line, and a fourth line connecting the fourth line and the fourth line. the fifth line connecting the second line and the first battery negative terminal; a third switch controlling the conduction and interruption of the fifth line; a sixth line connecting the first line, a portion of the first line closer to the charger positive terminal than the connection point between the first line and the fourth line, and the load positive terminal; a seventh line connecting the second line, a portion of the second line closer to the charger negative terminal than the connection point between the second line and the fifth line, and the load negative terminal; a control means for controlling the conduction and interruption states of the first switch, the second switch, and the third switch; a first fuse provided in the third line; a second fuse provided in the fourth line and having a lower current-carrying capacity than the first fuse; and a third fuse provided in the fifth line and having a lower current-carrying capacity than the first fuse. Effect of the Invention

[0009] According to the present disclosure, it is possible to provide a power distribution device that is capable of switching between series connection and parallel connection of batteries and can more appropriately respond to both external short circuits and battery short circuits. [Brief description of the drawings]

[0010] [Figure 1]1 is a configuration diagram showing a secondary battery system including a power distribution device according to an embodiment of the present invention. [Diagram 2] 2 is a block diagram showing details of a control unit shown in FIG. 1. [Diagram 3] 2 is a first state diagram showing a control state by a SW control unit shown in FIG. 1. [Figure 4] 1. FIG. 4 is a second state diagram showing a control state by the SW control unit shown in FIG. [Diagram 5] FIG. 1 is a state diagram showing the current flow in each short-circuit state, illustrating the current flow when an external short circuit occurs on the charger side in a series connection. [Figure 6] FIG. 1 is a state diagram showing the current flow in each short-circuit state, illustrating the current flow when an external short circuit occurs on the high-voltage load side in a series connection. [Figure 7] FIG. 1 is a state diagram showing the current flow in each short-circuit state, illustrating the current flow when an external short circuit occurs on the charger side in a parallel connection. [Figure 8] 11 is a state diagram showing the current flow in each short-circuit state, illustrating the current flow when the first battery is short-circuited. [Figure 9] FIG. 11 is a state diagram showing the current flow in each short-circuit state, illustrating the current flow when the second battery is short-circuited. [Figure 10] FIG. 13 is a configuration diagram showing a secondary battery system according to a modified example of the present embodiment. [Figure 11] 11 is a block diagram showing details of a control unit according to the modified example shown in FIG. 10. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention will be described below along with preferred embodiments. Note that the present invention is not limited to the embodiments shown below, and can be modified as appropriate within the scope of the present invention. In addition, in the embodiments shown below, some configurations are omitted from illustration and description, but it goes without saying that publicly known or well-known technologies are appropriately applied to the details of the omitted technologies within the scope of the contents described below.

[0012] Fig. 1 is a configuration diagram showing a secondary battery system including a power distribution device according to this embodiment. The secondary battery system 1 shown in Fig. 1 includes a high-voltage battery 10, a charging junction box (hereinafter referred to as J / B) 20, a quick charger (charger) 30, a high-voltage J / B 40, a high-voltage load (load) 50, and a power distribution device 60.

[0013] The high-voltage battery 10 includes a first battery 11, a second battery 12, a first monitoring unit 13, a second monitoring unit 14, and a battery ECU (Electronic Control Unit) 15.

[0014] The first battery 11 and the second battery 12 are configured by secondary batteries such as chargeable and dischargeable lithium ion batteries. The first battery 11 and the second battery 12 are each capable of supplying a high voltage such as 400V in order to drive a high voltage load 50 in an electric vehicle, for example. In this embodiment, the first battery 11 and the second battery 12 are assumed to have the same voltage.

[0015] The first monitoring unit 13 monitors the voltage, current, and temperature of the first battery 11. The second monitoring unit 14 monitors the voltage, current, and temperature of the second battery 12. The battery ECU 15 calculates the charging rates of the first battery 11 and the second battery 12 based on information from the first monitoring unit 13 and the second monitoring unit 14. The battery ECU 15 may also calculate the deterioration levels and detect abnormalities of the first battery 11 and the second battery 12.

[0016] The charging J / B 20 is a relay device interposed between the power distribution device 60 and the rapid charger 30. The charging J / B 20 includes a first charging relay 21 and a second charging relay 22. The first charging relay 21 controls the connection between the positive electrode side of the rapid charger 30 and the power distribution device 60. The second charging relay 22 controls the connection between the negative electrode side of the rapid charger 30 and the power distribution device 60. The first charging relay 21 and the second charging relay 22 may be either of a mechanical contact type or a semiconductor type. The same applies to first and second high-voltage relays 41, 42 and first to third switches SW1 to SW3 described later.

[0017] The quick charger 30 supplies power for charging the first battery 11 and the second battery 12 through the charging J / B 20 and the power distribution device 60. The quick charger 30 may supply power with a voltage of 400V, for example, or may supply power with a voltage of 800V. The power distribution device 60 determines whether the first battery 11 and the second battery 12 are connected in series or in parallel according to the supply power, and charges the first battery 11 and the second battery 12 in that connection state. Note that the secondary battery system 1 according to this embodiment is assumed to be charged by the quick charger 30, but is not limited thereto, and may be charged by a general charger that is not quick.

[0018] The high voltage J / B 40 is a relay device interposed between the power distribution device 60 and the high voltage load 50. The high voltage J / B 40 includes a first high voltage relay 41 and a second high voltage relay 42. The first high voltage relay 41 controls the connection between the positive electrode side of the high voltage load 50 and the power distribution device 60. The second high voltage relay 42 controls the connection between the negative electrode side of the high voltage load 50 and the power distribution device 60. The high voltage load 50 is a motor or the like that generates driving force for a vehicle.

[0019] The power distribution device 60 switches the connection state of the first battery 11 and the second battery 12 between a series state and a parallel state when charging from the quick charger 30 via the charging J / B 20, or when discharging to the high-voltage load 50 via the high-voltage J / B 40.

[0020] The power distribution device 60 has a plurality of terminals 60a to 60h. The first battery positive terminal 60a and the first battery negative terminal 60b are terminals connected to the positive and negative electrodes of the first battery 11, respectively. The second battery positive terminal 60c and the second battery negative terminal 60d are terminals connected to the positive and negative electrodes of the second battery 12, respectively. The charger positive terminal 60e and the charger negative terminal 60f are terminals connected to the positive and negative electrodes of the quick charger 30, respectively. The load positive terminal 60g and the load negative terminal 60h are terminals connected to the positive and negative electrodes of the high-voltage load 50, respectively.

[0021] Furthermore, the power distribution device 60 includes a plurality of lines L1 to L7, a plurality of switches SW1 to SW3, a plurality of fuses F1 to F3, a plurality of current sensors 61, a voltage sensor 62, and a control unit (control means) 63.

[0022] The first line L1 connects the first battery positive terminal 60a and the charger positive terminal 60e. The second line L2 connects the second battery negative terminal 60d and the charger negative terminal 60f. The third line L3 connects the second battery positive terminal 60c and the first battery negative terminal 60b. As described later, one end of the third line L3 (from the terminal 60c to the connection point P1 in FIG. 1) is shared with the fourth line L4, and the other end (from the terminal 60b to the connection point P2 in FIG. 1) is shared with the fifth line L5. The third line L3 connects the first battery negative terminal 60b and the second battery positive terminal 60c through the shared parts L34 and L35. The first switch SW1 controls the conduction and cutoff of the third line L3, and is provided at a position of the third line L3 excluding the shared parts L34 and L35.

[0023] The fourth line L4 connects the second battery positive terminal 60c and the first line L1. One end of the fourth line L4 is a common portion L34 with the third line L3. The second switch SW2 controls the conduction and cutoff of the fourth line L4, and is provided at a position of the fourth line L4 excluding the common portion L34 with the third line L3.

[0024] The fifth line L5 connects the second line L2 and the first battery negative terminal 60b. The other end of the fifth line L5 is a common portion L35 with the third line L3. The third switch SW3 controls the conduction and cutoff of the fifth line L5, and is provided at a position of the fifth line L5 excluding the common portion L35 with the third line L3.

[0025] The sixth line L6 connects a connection point P4 of the first line L1, which is located closer to the charger positive terminal 60e than the connection point P3 with the fourth line L4, to the load positive terminal 60g. The seventh line L7 connects a connection point P6 of the second line L2, which is located closer to the charger negative terminal 60f than the connection point P5 with the fifth line L5, to the load negative terminal 60h.

[0026] The first to third fuses F1 to F3 are mechanical fuses that melt when an overcurrent flows. Among these fuses F1 to F3, the second and third fuses F2 and F3 have a lower current carrying capacity than the first fuse F1. Here, the first fuse F1 is provided on the third line L3, particularly at a position on the third line L3 excluding the common parts L34 and L35. The second fuse F2 is provided on the fourth line L4, particularly at a position on the fourth line L4 excluding the common part L34. Furthermore, the third fuse F3 is provided on the fifth line L5, particularly at a position on the fifth line L5 excluding the common part L35. Specifically, in this embodiment, the first fuse F1 is provided on the first battery negative terminal 60b side of the first switch SW1. The second fuse F2 is provided on the connection point P3 side of the second switch SW2. The third fuse F3 is provided on the connection point P5 side of the third switch SW3.

[0027] The current sensor 61 is provided on each of the fourth line L4 and the fifth line L5, and outputs a signal corresponding to the current in the fourth line L4 and a signal corresponding to the current in the fifth line L5. In this embodiment, the current sensor 61 is provided on a common portion L34 between the third line L3 and the fourth line L4, and on a common portion L35 between the third line L3 and the fifth line L5.

[0028] The voltage sensor 62 outputs a signal corresponding to the potential difference between the first line L1 and the second line L2. More specifically, the voltage sensor 62 outputs a signal corresponding to the potential difference between a connection point P7 located between the connection points P3 and P4 on the first line L1 and a connection point P8 located between the connection points P5 and P6 on the second line L2.

[0029] Fig. 2 is a block diagram showing details of the control unit 63 shown in Fig. 1. The control unit 63 controls the entire power distribution device 60, and includes a SW control unit 63a, a voltage measurement unit 63b, a current measurement unit (current measurement means) 63c, and a failure determination unit 63d.

[0030] The SW control unit 63a controls the conductive state (ON) and the cut-off state (OFF) of the first switch SW1, the second switch SW2, and the third switch SW3. FIG. 3 and FIG. 4 are state diagrams showing the control state by the SW control unit 63a shown in FIG. 2. First, as shown in FIG. 3, when the SW control unit 63a wants to connect the first battery 11 and the second battery 12 in series, the SW control unit 63a turns on the first switch SW1 and turns off the second switch SW2 and the third switch SW3. As a result, for example, during charging, a route (see the thick line) of the first line L1, the first battery 11, the third line L3, the second battery 12, and the second line L2 is formed. Therefore, the first battery 11 and the second battery 12 are in a series state. On the other hand, as shown in FIG. 4, when the SW control unit 63a wants to connect the first battery 11 and the second battery 12 in parallel, the SW control unit 63a turns off the first switch SW1 and turns on the second switch SW2 and the third switch SW3. As a result, during charging, a route (see thick line) of the first line L1, the first battery 11, the fifth line L5, and the second line L2, and a route (see thick line) of the first line L1, the fourth line L4, the second battery 12, and the second line L2 are formed. Therefore, the first battery 11 and the second battery 12 are in a parallel state.

[0031] The voltage measurement unit 63b measures a voltage corresponding to the potential difference between the first line L1 and the second line L2 in response to a signal from the voltage sensor 62. The current measurement unit 63c measures a current in the fourth line L4 (particularly the common portion L34) and a current in the fifth line L4 (particularly the common portion L35) in response to a signal from the current sensor 61.

[0032] The fault determination unit 63d determines faults such as an external short circuit, a battery short circuit, etc. Based on the voltage measured by the voltage measurement unit 63b and the current measured by the current measurement unit 63c, the fault determination unit 63d determines an external short circuit on the quick charger 30 side or the high voltage load 50 side, or a battery short circuit when the first switch SW1, the second switch SW2, or the third switch SW3 fails.

[0033] For example, if an external short circuit occurs when the first and second batteries 11, 12 are connected in series, an overcurrent flows on the third line L3. Also, if an external short circuit occurs when the first and second batteries 11, 12 are connected in parallel, an overcurrent flows on the fourth line L4 and the fifth line L5. Furthermore, if a battery short circuit occurs in the first battery 11 or the second battery 12, an overcurrent flows in some locations. The failure determination unit 63d determines whether there is such a current tendency based on the measurement results of the current measurement unit 63c, and determines whether there is an external short circuit or a battery short circuit.

[0034] The failure determination unit 63d according to the present embodiment can also determine failures of the first switch SW1, the second switch SW2, and the third switch SW3 based on the measurement results of the current measurement unit 63c and the voltage measurement unit 63b. The first switch SW1, the second switch SW2, and the third switch SW3 may have an ON failure in which they are always on, and an OFF failure in which they are always off. The failure determination unit 63d can determine such failures. For example, suppose that the voltage measurement unit 63b detects a voltage of 400V even though the SW control unit 63a turns off all the switches SW1 to SW3. In this case, it can be said that one of the second switch SW2 and the third switch SW3 has an ON failure. The failure determination unit 63d determines a failure by such voltage measurement. Furthermore, in this case, for example, when the current measurement unit 63c measures a predetermined current in the common part L34 and detects zero current in the common part L35, the failure determination unit 63d identifies the second switch SW2 as an ON failure.

[0035] Next, the operation according to this embodiment will be described. Figures 5 to 9 are state diagrams showing the current flow in each short-circuit state.

[0036] First, assume that an external short circuit occurs on the quick charger 30 side during series connection as shown in Fig. 5. In this case, an overcurrent flows through the route of the first line L1, the first battery 11, the third line L3, the second battery 12, and the second line L2. In this case, since the first fuse F1 is provided on the third line L3, the first fuse F1 melts down, making it possible to appropriately deal with the external short circuit on the quick charger 30 side during series connection.

[0037] 6, assume that an external short circuit occurs on the high voltage load 50 side during series connection. In this case, an overcurrent flows through the route of the sixth line L6, the first line L1 (from the first battery positive terminal 60a to the connection point P4), the first battery 11, the third line L3, the second battery 12, the second line L2 (from the second battery negative terminal 60d to the connection point P6), and the seventh line L7. In this case, since the first fuse F1 is provided on the third line L3, the first fuse F1 melts down to appropriately deal with the external short circuit on the high voltage load 50 side during series connection.

[0038] 7, assume that an external short circuit occurs on the quick charger 30 side during parallel connection. In this case, an overcurrent flows through both the route of the first line L1, the first battery 11, the fifth line L5, and the second line L2 (from the connection point P5 to the charger negative terminal 60f) and the route of the first line L1 (from the connection point P3 to the charger positive terminal 60e), the fourth line L4, the second battery 12, and the second line L2. In this case, since the second fuse F2 is provided on the fourth line L4 and the third fuse F3 is provided on the fifth line L5, both fuses F2 and F3 are melted to appropriately deal with the external short circuit on the quick charger 30 side during parallel connection.

[0039] In this embodiment, it is assumed that the parallel connection is performed only during charging, but this is not particularly limited, and when a parallel connection is performed when operating the high-voltage load 50, an external short circuit on the high-voltage load 50 side can be similarly dealt with.

[0040] Also, as shown in FIG. 8, for example, when the second switch SW2 has an ON fault, the SW control unit 63a attempts to connect the batteries in series. In this case, a route is formed that includes the first line L1 (from the first battery positive terminal 60a to the connection point P3), the first battery 11, the third line L3 (from the first battery negative terminal 60b to the connection point P1), and the fourth line L4 (from the connection point P1 to the connection point P3), causing a battery short circuit. Thus, an overcurrent flows along this route. Here, since the first fuse F1 and the second fuse F2 are provided along the route, the second fuse F2, which has a lower current carrying capacity, melts down relatively early. Thus, the battery short circuit of the first battery 11 can be appropriately dealt with.

[0041] 9, for example, when the third switch SW3 has an ON fault, the SW control unit 63a attempts to connect the batteries in series. In this case, a route is formed that includes the third line L3 (from the connection point P2 to the second battery positive terminal 60c), the second battery 12, the second line L2 (from the connection point P5 to the connection point P5), and the fifth line L5 (from the connection point P5 to the connection point P2), causing a battery short circuit. Thus, an overcurrent flows along this route. Here, since the first fuse F1 and the third fuse F3 are provided along the route, the third fuse F3, which has a lower current carrying capacity, melts down relatively early. Thus, the battery short circuit of the second battery 12 can be appropriately dealt with.

[0042] In this manner, the power distribution device 60 according to the present embodiment has the above-mentioned circuit configured, so that when a series connection is desired, the first switch SW1 is turned on and the second and third switches SW2 and SW3 are turned off. In this case, in the event of an external short circuit, the first fuse F1 is used to cut off the power, making it possible to appropriately deal with an external short circuit during a series connection.

[0043] In addition, since the above circuit is constructed, when a parallel connection is desired, the first switch SW1 is turned off and the second and third switches SW2, SW3 are turned on. In this case, in the event of an external short circuit, both the second fuse F2 and the third fuse F3 will be cut off. In particular, since the current carrying capacity of the second fuse F2 and the third fuse F3 is lower than that of the first fuse F1, the time until cut off is unlikely to become long in the event of an external short circuit during parallel connection, and it is possible to appropriately deal with an external short circuit during parallel connection.

[0044] Furthermore, in the event of a switch failure causing both the first switch SW1 and the second switch SW2 to be turned on, a route is formed that connects the positive electrode of the first battery 11 through the second fuse F2 and the first fuse F1 in this order to the negative electrode of the first battery 11. In this case, the fuse is cut off by the second fuse F2, which has a lower current carrying capacity out of the first fuse F1 and the second fuse F2, and it is possible to appropriately deal with a battery short circuit on the first battery 11 side.

[0045] In addition, if a switch failure occurs causing both the first switch SW1 and the third switch SW3 to be on, a route is formed that connects the positive electrode of the second battery 12 through the first fuse F1 and the third fuse F3 in this order to the negative electrode of the second battery 12. In this case, the fuse is cut off by the third fuse F3, which has a lower current carrying capacity than the first fuse F1 and the third fuse F3, and it is possible to appropriately deal with a battery short circuit on the second battery 12 side.

[0046] As described above, it is possible to provide a power distribution device 60 that is capable of switching between series connection and parallel connection of the batteries 11, 12 and is capable of dealing more appropriately with both an external short circuit and a battery short circuit.

[0047] Also, by providing the shared portions L34 and L35, it is possible to contribute to simplifying the circuit by sharing a part of the third line L3 and the fourth line L4, and a part of the third line L3 and the fifth line L5. Furthermore, by providing the first to third fuses F1 to F3 at positions other than the shared portions L34 and L35, it is possible to provide the fuses F1 to F3 at appropriate positions.

[0048] The present invention has been described above based on an embodiment, but the present invention is not limited to the above embodiment, and modifications may be made without departing from the spirit of the present invention, and if possible, known or well-known technologies may be combined.

[0049] Fig. 10 is a configuration diagram showing a secondary battery system 1 showing a modification of the present embodiment. In the modification shown in Fig. 10, the power distribution device 60 has a first fuse F1, a second fuse F2, and a third fuse F3 which are not mechanical fuses that melt due to an overcurrent, but are electronic fuses such as pyro fuses and semiconductor fuses. In particular, in this embodiment, the first fuse F1, the second fuse F2, and the third fuse F3 are configured to be cut off in response to a signal from the outside.

[0050] FIG. 11 is a block diagram showing details of the control unit 63 according to the modified example shown in FIG. 10. As shown in FIG. 11, the control unit 63 includes a cutoff control unit (cutoff control means) 63e. The cutoff control unit 63e is capable of selectively cutting off the first to third fuses F1 to F3, which are electronic, and is configured to transmit a signal to one of the first to third fuses F1 to F3 to be cut off. Here, when an external short circuit occurs during the series connection shown in FIG. 5 and FIG. 6, an overcurrent flows through both of the common parts L34 and L35. Therefore, the failure determination unit 63d can determine an external short circuit when the current measurement unit 63c detects that a current larger than normal (but lower than an overcurrent) flows through both of the common parts L34 and L35. In such a case, the cutoff control unit 63e determines that an overcurrent will flow in the future and cuts off the first fuse F1. Similarly, for the external short circuit shown in FIG. 7, the cutoff control unit 63e cuts off the second fuse F2 and the third fuse F3. In addition, the cutoff control unit 63e also cuts off the second fuse F2 or the third fuse F3 in the same manner in the event of a battery short circuit.

[0051] In this manner, in the modified example, the current in each of the common portion L34 and the common portion L35 is measured, and the first fuse F1, the second fuse F2, and the third fuse F3, which are electronic fuses, are selectively cut off by the cutoff control unit 63e. Therefore, unlike mechanical fuses, the flow of an overcurrent is not required for cutting off, and abnormality detection is performed before an overcurrent flows, making it possible to cut off an appropriate portion.

[0052] In the above description, the first fuse F1 is provided on the third line L3 closer to the first battery negative terminal 60b than the first switch SW1, but this is not limiting and the first fuse F1 may be provided on the second battery positive terminal 60c. Similarly, the second fuse F2 may be provided on the connection point P1 side than the second switch SW2. Furthermore, the third fuse F3 may be provided on the connection point P2 side than the third switch SW3. [Explanation of symbols]

[0053] 1: Secondary battery system 11: First battery 12: Second battery 30: Rapid charger (charger) 50: High pressure load (load) 60: Power distribution equipment 60a: First battery positive terminal 60b: First battery negative terminal 60c: Second battery positive terminal 60d: Second battery negative terminal 60e: Charger positive terminal 60f: Charger negative terminal 60g: Load positive terminal 60h: Load negative terminal 61: Current sensor 62: Voltage sensor 63: Control unit (control means) 63a: SW control section 63b: Voltage measurement section 63c: Current measurement unit (current measurement means) 63d:Failure determination section 63e: shutoff control section (shutoff control means) F1: First fuse F2: Second fuse F3: Third fuse L1: First line L2: Second line L3: Third line L4: 4th line L5: 5th line L6: 6th line L7: 7th line L34:Common part L35:Common part P3: Connection point P5: Connection point SW1: First switch SW2: Second switch SW3: Third switch

Claims

1. a first battery positive terminal and a first battery negative terminal connected to the positive and negative electrodes of the first battery, respectively; a second battery positive terminal and a second battery negative terminal connected to the positive and negative electrodes of the second battery, respectively; a charger positive terminal and a charger negative terminal connected to the positive and negative electrodes of the charger, respectively; a load positive terminal and a load negative terminal connected to the positive and negative electrodes of the load, respectively; a first line connecting the first battery positive terminal and the charger positive terminal; a second line connecting the second battery negative terminal and the charger negative terminal; a third line connecting the second battery positive terminal and the first battery negative terminal; a first switch that controls conduction and interruption in the third line; a fourth line connecting the second battery positive terminal and the first line; a second switch that controls the connection and disconnection of the fourth line; a fifth line connecting the second line and the first battery negative terminal; a third switch that controls the conduction and interruption of the fifth line; a sixth line connecting the charger positive terminal side of the first line relative to a connection point between the first line and the fourth line and the load positive terminal; a seventh line connecting the charger negative terminal side of the second line relative to a connection point between the second line and the fifth line and the load negative terminal; a control unit for controlling a conductive state and a cut-off state of the first switch, the second switch, and the third switch; a first fuse provided in the third line; a second fuse provided in the fourth line and having a current carrying capacity lower than that of the first fuse; a third fuse provided in the fifth line and having a current carrying capacity lower than that of the first fuse; A power distribution device comprising:

2. When one end side of the fourth line is shared with the third line and connected to the second battery positive terminal, and one end side of the fifth line is shared with the third line and connected to the first battery negative terminal, the first fuse is provided at a position of the third line excluding a portion shared with the fourth line and the fifth line, the second fuse is provided at a position of the fourth line excluding a portion shared with the third line, and the third fuse is provided at a position of the fifth line excluding a portion shared with the third line. The power distribution device according to claim 1 .

3. The first fuse, the second fuse, and the third fuse are electronic fuses that can be cut off in response to an external signal, The control means a current measuring means for measuring a current in a common portion between the third line and the fourth line and a common portion between the third line and the fifth line; and a cutoff control means for selectively cutting off the first fuse, the second fuse, and the third fuse based on the current measured by the current measuring means. The power distribution device according to claim 2 .

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