WO2024105796A1

WO2024105796A1 - Switching device and switching system

Info

Publication number: WO2024105796A1
Application number: PCT/JP2022/042471
Authority: WO
Inventors: 真輔立崎
Original assignee: 住友電気工業株式会社; 住友電装株式会社; 株式会社オートネットワーク技術研究所
Priority date: 2022-11-16
Filing date: 2022-11-16
Publication date: 2024-05-23

Abstract

This switching system includes: a plurality of batteries; a plurality of parallel connection switches that switch the plurality of batteries into a state of parallel connection; one or more serial connection switches that switch the plurality of batteries into a serial connection state; and a plurality of parallel connection circuit breakers. The plurality of parallel connection circuit breakers are each disposed on a route through which current flows regardless of whether the plurality of batteries are in the parallel connection state or in the serial connection state, and are serially connected on a one-to-one basis with each of the plurality of batteries. Through on/off operations of the parallel connection and serial connection switches, the plurality of batteries enter the parallel connection state or the serial connection state, and the opening of each of the plurality of parallel connection circuit breakers releases the corresponding battery from the parallel connection state.

Description

Switching Device and Switching System

This disclosure relates to a switching device and a switching system.

A system capable of switching between a series connection and a parallel connection of multiple batteries is known. Such a system is described in the following Patent Document 1. The system of Patent Document 1 equalizes the voltages of multiple batteries when switching from a series connection to a parallel connection of multiple batteries. With reference to FIG. 1, this system includes multiple batteries BT1 and BT2, and multiple relays RY1, ..., and RY7. For a load 900 connected to the system, relays RY1 and RY3 are turned on, and relay RY2 is turned off, and then relays RY4 and RY5 are turned on. As a result, power is supplied to the load 900 from the parallel-connected batteries BT1 and BT2. When an external charger 902 for rapid charging is connected to the system, for example, relays RY1 and RY3 are turned off, and relay RY2 is turned on, and then relays RY6 and RY7 are turned on. As a result, the series-connected batteries BT1 and BT2 are rapidly charged by a high voltage.

JP 2021-16267 A

　A switching system according to one aspect of the present disclosure includes multiple batteries, multiple parallel connection switches that connect the multiple batteries in parallel, one or more series connection switches that connect the multiple batteries in series, and multiple parallel connection circuit breakers, each of which is arranged in a path through which current flows whether the multiple batteries are in a parallel connection state or a series connection state, and is connected in series with each of the multiple batteries in a one-to-one relationship, the multiple batteries are connected in parallel or series by turning on and off the parallel connection switch and the series connection switch, and each of the multiple parallel connection circuit breakers disconnects the corresponding battery from the parallel connection state by opening.

FIG. 1 is a circuit diagram showing the configuration of a conventional system in which two batteries can be connected in parallel or in series. FIG. 2 is a circuit diagram showing a configuration of a switching system according to an embodiment of the present disclosure. FIG. 3 is a circuit diagram showing a configuration of a switching device in the switching system shown in FIG. FIG. 4 is a block diagram showing a vehicle in which the switching system shown in FIG. 2 is installed. FIG. 5 is a circuit diagram showing a discharging state of two battery units connected in parallel in the switching system shown in FIG. FIG. 6 is a circuit diagram showing a state in which a short-circuit current flows due to a malfunction of the series-connected switch in FIG. FIG. 7 is a circuit diagram showing a state in which the fuse serving as the parallel connection breaker in FIG. 5 is blown. FIG. 8 is a circuit diagram showing a state in which a current flows that short-circuits the output terminals of the DC power supply. FIG. 9 is a circuit diagram showing a state in which the fuse, which is the series-connected breaker in FIG. 8, is blown. FIG. 10 is a circuit diagram showing a configuration of a switching system according to a comparative example. FIG. 11 is a circuit diagram showing the discharging state of two batteries connected in parallel in the switching system shown in FIG. FIG. 12 is a circuit diagram showing a state in which a short-circuit current flows due to a malfunction of the series-connected switch in FIG. FIG. 13 is a circuit diagram showing a state in which the fuse, which is the parallel connection breaker in FIG. 11, is blown. FIG. 14 is a circuit diagram showing a configuration of a switching system according to a first modified example. FIG. 15 is a circuit diagram showing a configuration of a switching system according to a second modified example. FIG. 16 is a circuit diagram showing a configuration of a switching system according to a third modified example. FIG. 17 is a circuit diagram showing a discharging state of three battery units connected in parallel in the switching system shown in FIG. FIG. 18 is a circuit diagram showing a state in which a short-circuit current flows due to a malfunction of the series-connected switch in FIG. FIG. 19 is a circuit diagram showing possible locations of series-connected circuit breakers in the switching system shown in FIG.

[Problem to be solved by this disclosure]
In the system of Patent Document 1, if a malfunction occurs in a relay that switches the connection state of batteries BT1 and BT2 between a series connection or a parallel connection, there is a problem that the batteries etc. may be damaged.

Therefore, the present disclosure aims to provide a switching device and switching system that can switch between a series connection and a parallel connection of multiple batteries and can avoid damage to the batteries, etc.

[Effects of the present disclosure]
According to the present disclosure, it is possible to provide a switching device and a switching system that can switch between series connection and parallel connection of a plurality of batteries and can avoid damage to the batteries, etc.

[Description of the embodiments of the present disclosure]
The contents of the embodiments of the present disclosure will be listed and described below. At least some of the embodiments described below may be combined in any combination.

(1) A switching system according to a first aspect of the present disclosure includes a plurality of batteries, a plurality of parallel connection switches that connect the plurality of batteries in a parallel connection state, one or more series connection switches that connect the plurality of batteries in a series connection state, and a plurality of parallel connection circuit breakers, each of which is disposed in a path through which current flows whether the plurality of batteries are in a parallel connection state or a series connection state, and is connected in series with each of the plurality of batteries in a one-to-one relationship, the plurality of batteries are brought into a parallel connection state or a series connection state by the on/off operation of the parallel connection switch and the series connection switch, and each of the plurality of parallel connection circuit breakers is opened to separate the corresponding battery from the parallel connection state. This makes it possible to switch between a series connection and a parallel connection of the plurality of batteries, and to avoid damage to the batteries, etc.

(2) In the above (1), the switching system may further include a pair of external connection terminals for connecting the multiple batteries to an external device, and a series connection circuit breaker disposed on a line connecting the pair of external connection terminals to each other, the series connection circuit breaker being formed by opening all of the multiple parallel connection circuit breakers when the multiple parallel connection switches are on and the series connection switch is on. This makes it possible to prevent the output terminal of the DC power supply from being short-circuited even if the series connection switch malfunctions and turns on when the multiple batteries are connected in parallel and being charged by a DC power supply.

(3) In the above (2), the series connection breaker may be connected in series with any one of the one or more series connection switches. This allows the external connection terminal to be quickly opened when a series connection switch connected to the series connection breaker malfunctions and turns on when multiple batteries are connected in parallel.

(4) In any one of (1) to (3) above, the switching system may further include a control unit that controls the on/off operation of each of the multiple parallel connection switches and the one or more series connection switches. This allows the multiple batteries to be efficiently connected in parallel or in series.

(5) In any one of (1) to (4) above, at least one of the multiple parallel connection switches and the one or more series connection switches may include a relay. This allows the multiple batteries to be efficiently connected in parallel or in series.

(6) In any one of (1) to (5) above, at least one of the multiple parallel-connected circuit breakers may include a fuse. This makes it possible to reliably avoid short-circuiting of the batteries even if the series-connected switch malfunctions and turns on when multiple batteries are connected in parallel.

(7) In any one of (1) to (6) above, the switching system may be mounted on a vehicle. This prevents damage to the vehicle battery and does not affect external devices even if the series connection switch malfunctions and turns on when multiple vehicle batteries are connected in parallel.

(8) A switching device according to a second aspect of the present disclosure is a switching device disposed between a plurality of batteries and an external device, and includes a plurality of parallel connection switches that connect the plurality of batteries to a parallel connection state and the external device, one or more series connection switches that connect the plurality of batteries to a series connection state and the external device, and a plurality of parallel connection circuit breakers, each of which is disposed in a path through which current flows whether the plurality of batteries are in a parallel connection state or a series connection state, and is connected in series with each of the plurality of batteries in a one-to-one relationship, and the parallel connection switch and the series connection switch are turned on and off to bring the plurality of batteries into a parallel connection state or a series connection state, and each of the plurality of parallel connection circuit breakers is opened to separate the corresponding battery from the parallel connection state. This makes it possible to switch between a series connection and a parallel connection of the plurality of batteries, and to avoid damage to the batteries, etc.

(9) In the above (8), the switching device may further include a pair of external connection terminals for connecting the multiple batteries to an external device, and a series connection circuit breaker disposed on a line connecting the pair of external connection terminals to each other, the series connection circuit breaker being formed by opening all of the multiple parallel connection circuit breakers when the multiple parallel connection switches are on and the series connection switch is on. This makes it possible to avoid maintaining a short circuit at the output terminal of the DC power supply even if the series connection switch malfunctions and turns on when the multiple batteries are connected in parallel and being charged by a DC power supply.

(10) In the above (9), the series connection breaker may be connected in series with any one of the one or more series connection switches. This allows the external connection terminal to be quickly opened when a series connection switch connected to the series connection breaker malfunctions and turns on when multiple batteries are connected in parallel.

(11) In any one of (8) to (10) above, the switching device may further include a control unit that controls the on/off operation of each of the multiple parallel connection switches and the one or more series connection switches. This allows the multiple batteries to be efficiently connected in parallel or in series.

(12) In any one of (8) to (11) above, at least one of the multiple parallel connection switches and the one or more series connection switches may include a relay. This allows the multiple batteries to be efficiently connected in parallel or in series.

(13) In any one of (8) to (12) above, at least one of the multiple parallel-connected circuit breakers may include a fuse. This makes it possible to reliably avoid short-circuiting of the batteries even if the series-connected switch malfunctions and turns on when multiple batteries are connected in parallel.

(14) In any one of (8) to (13) above, the switching device may be mounted on a vehicle. This prevents damage to the vehicle battery and does not affect external devices even if the series connection switch malfunctions and turns on when multiple vehicle batteries are connected in parallel.

[Details of the embodiment of the present disclosure]
In the following embodiments, the same parts are denoted by the same reference numerals, and their names and functions are also the same, so detailed description thereof will not be repeated.

Referring to FIG. 2, the switching system 100 according to the embodiment of the present disclosure includes a first battery unit 102, a second battery unit 104, a first parallel connection switch 110, a second parallel connection switch 112, and a first series connection switch 114. The switching system 100 also includes a first parallel connection breaker 120, a second parallel connection breaker 122, a series connection breaker 124, a control unit 130, a first external connection terminal 132, and a second external connection terminal 134. The first battery unit 102 and the second battery unit 104 are units of the same specification, which are composed of a rechargeable and dischargeable storage battery. The first battery unit 102 and the second battery unit 104 are, for example, battery units of 400V specification (i.e., the rated charging voltage and output voltage are 400V). Note that the battery unit is not limited to being composed of multiple batteries, but also includes being composed of one battery.

The first parallel connection switch 110, the second parallel connection switch 112, and the first series connection switch 114 short-circuit (hereinafter referred to as "on") or open (hereinafter referred to as "off") both terminals of each switch under the control of the control unit 130. The short-circuiting and opening operations are also collectively referred to as on/off operations. Each of the first parallel connection switch 110, the second parallel connection switch 112, and the first series connection switch 114 is, for example, a relay. By using a relay, as described later, multiple batteries can be efficiently connected in parallel or in series under external control. Each of the first parallel connection switch 110, the second parallel connection switch 112, and the first series connection switch 114 may be a semiconductor element having a switching function, such as a FET (Field Effect Transistor) or an IGBT (Insulated Gate Bipolar Transistor).

The first parallel connection circuit breaker 120, the second parallel connection circuit breaker 122, and the series connection circuit breaker 124 connect their respective terminals with a low resistance value, and have the function of opening the connection between their respective terminals when a large current of a predetermined value or more flows. Here, each of the first parallel connection circuit breaker 120, the second parallel connection circuit breaker 122, and the series connection circuit breaker 124 is a fuse. When a large current flows through the fuse and the fuse becomes hot, it melts and opens the connection between the two terminals. By using a fuse, it is possible to reliably avoid a short circuit of the battery, as will be described later.

The first battery unit 102 and the first parallel connection circuit breaker 120 are directly connected in series, and the second battery unit 104 and the second parallel connection circuit breaker 122 are directly connected in series. "Direct" means that there is no other element between the two elements connected in series, and there is no connection to other elements. The first battery unit 102 and the first parallel connection circuit breaker 120 do not have to be directly connected. The second battery unit 104 and the second parallel connection circuit breaker 122 do not have to be directly connected either. The terminal of the first battery unit 102 that is not connected to the first parallel connection circuit breaker 120 (i.e., the negative terminal) is connected to the first parallel connection switch 110. The terminal of the second battery unit 104 that is not connected to the second parallel connection circuit breaker 122 (i.e., the positive terminal) is connected to the second parallel connection switch 112. A terminal (i.e., a negative terminal) of the first battery unit 102 that is not connected to the first parallel connection circuit breaker 120 and a terminal (i.e., a positive terminal) of the second battery unit 104 that is not connected to the second parallel connection circuit breaker 122 are connected via a first series connection switch 114. A terminal of the first parallel connection circuit breaker 120 that is not connected to the first battery unit 102 is connected to a terminal of the second parallel connection switch 112 that is not connected to the second battery unit 104. A connection node between the second parallel connection switch 112 and the first parallel connection circuit breaker 120 is connected to a first external connection terminal 132 via a series connection circuit breaker 124. A terminal of the second parallel connection circuit breaker 122 that is not connected to the second battery unit 104 is connected to a terminal of the first parallel connection switch 110 that is not connected to the first battery unit 102. A connection node between the first parallel connection switch 110 and the second parallel connection circuit breaker 122 is connected to a second external connection terminal 134.

By being configured in this manner, the first parallel connection switch 110, the second parallel connection switch 112, and the first series connection switch 114 can switch the connection state of the first battery unit 102 and the second battery unit 104. That is, the first battery unit 102 and the second battery unit 104 are connected in parallel by turning on the first parallel connection switch 110 and the second parallel connection switch 112 and turning off the first series connection switch 114. The first battery unit 102 and the second battery unit 104 are connected in series by turning off the first parallel connection switch 110 and the second parallel connection switch 112 and turning on the first series connection switch 114.

The control unit 130 outputs a control signal (see the three dashed arrows in FIG. 2) to control the on/off operation of the first parallel connection switch 110, the second parallel connection switch 112, and the first series connection switch 114. The control unit 130 can efficiently connect the first battery unit 102 and the second battery unit 104 in parallel or series. The control unit 130 can be configured as a control device (computer) including an arithmetic element (CPU: Central Processing Unit) and a storage element (memory), etc. The control unit 130 may be realized by a semiconductor integrated circuit such as an ASIC (Application Specific Integrated Circuit) or a programmable logic device (such as an FPGA (Field Programmable Gate Array)).

A load 900 or a power source 904 can be connected to the first external connection terminal 132 and the second external connection terminal 134. When charging the first battery unit 102 and the second battery unit 104, a charger (i.e., a DC power source) is connected as the power source 904. When the load 900 is connected, power can be supplied to the load 900 by discharging the first battery unit 102 and the second battery unit 104. In other words, the load 900 refers to an object (e.g., an electrical device) to which power is supplied from the first battery unit 102 and the second battery unit 104. The power source 904 refers to a device (e.g., a charger) that supplies power to the first battery unit 102 and the second battery unit 104. The load 900 and the power source 904 are collectively referred to as an external device.

In the switching system 100, a configuration for switching the connection state of the first battery unit 102 and the second battery unit 104 may be accommodated in a housing (not shown) to configure a switching device. Referring to FIG. 3, the switching device 140 accommodates the first parallel connection switch 110, the second parallel connection switch 112, the first series connection switch 114, the first parallel connection breaker 120, the second parallel connection breaker 122, and the series connection breaker 124 in a housing. The switching device 140 is a junction box for connecting the first battery unit 102 and the second battery unit 104 to an external device (i.e., a load 900 or a power source 904). The switching device 140 is connected to the load 900 or the power source 904 via the first external connection terminal 132 and the second external connection terminal 134. The switching device 140 is connected to the first battery unit 102 via

connection terminals

142 and 144, and to the second battery unit 104 via

connection terminals

146 and 148. The connection relationships of the elements shown in FIG. 3 are the same as those in FIG. 2. Note that, although FIG. 2 shows three signal lines for controlling the first parallel connection switch 110, the second parallel connection switch 112, and the first series connection switch 114 from the control unit 130, in FIG. 3, they are replaced by a single signal line.

(Mounting in a vehicle)
4, the switching system 100 shown in FIG. 2 may be mounted on a vehicle 170 such as a plug-in hybrid electric vehicle (PHEV) or an electric vehicle (EV). The switching system 100 mounted on the vehicle 170 constitutes a power supply unit. While the vehicle 170 is traveling, the switching system 100 turns on and off the first parallel connection switch 110, the second parallel connection switch 112, and the first series connection switch 114 to connect, for example, the first battery unit 102 and the second battery unit 104 in parallel. The output voltage (i.e., DC voltage) is supplied to a power converter 172. The power converter 172 has a function of a DC/DC converter and a function of an AC/DC converter. The DC voltage supplied to the power converter 172 is converted to a predetermined DC voltage by the function of the DC/DC converter of the power converter 172 and supplied to the inverter 174. The DC voltage supplied to the inverter 174 is converted to an AC voltage by the inverter 174 and used to drive a motor 176. Note that the output voltage of the switching system 100 may be supplied directly to the inverter 174 without passing through the power converter 172.

The output voltage of the switching system 100 is converted to a low voltage by the DC/DC converter function of the power converter 172 and supplied to the auxiliary load 178. This causes the auxiliary load 178 to operate. The auxiliary load 178 is an accessory device required to operate the engine and motor, and mainly includes a starter motor, an alternator, a radiator cooling fan, etc. The auxiliary load 178 may also include lighting, a wiper drive, a navigation device, an air conditioner, a heater, etc.

When charging the vehicle 170 (specifically, the first battery unit 102 and the second battery unit 104), the power converter 172 converts the AC power supplied from an external charger (AC power source) into a charging voltage for the first battery unit 102 and the second battery unit 104 by using the function of an AC/DC converter. The switching system 100 (specifically, the control unit 130) turns on and off the first parallel connection switch 110, the second parallel connection switch 112, and the first series connection switch 114, and connects the first battery unit 102 and the second battery unit 104 in parallel or in series depending on the voltage supplied from the external power source. For example, if the first battery unit 102 and the second battery unit 104 are of 400V specification and 400V is supplied from the charger, the first battery unit 102 and the second battery unit 104 are connected in parallel. If 800V is supplied from the charger, the first battery unit 102 and the second battery unit 104 are connected in series. This allows the first battery unit 102 and the second battery unit 104 to be compatible with two types of chargers with different charging voltages, and to be charged with the appropriate charging voltage. In addition, the power converter 172 may convert DC power from the first battery unit 102 and the second battery unit 104 into AC power using the function of an AC/DC converter, and supply the AC power to electrical devices (e.g., home appliances) outside the vehicle 170.

(In the event of a malfunction)
5 to 9, a description will be given of an operation for avoiding damage caused by a malfunction of the first series connection switch 114 when the first battery unit 102 and the second battery unit 104 are connected in parallel. With reference to Fig. 5, when the first battery unit 102 and the second battery unit 104 are connected in parallel, under the control of the control unit 130, the first parallel connection switch 110 and the second parallel connection switch 112 are turned on, and the first series connection switch 114 is turned off.

(When discharging)
5, a current flows and power is supplied to the load 900 connected to the first external connection terminal 132 and the second external connection terminal 134. The voltage between the first external connection terminal 132 and the second external connection terminal 134 is the voltage V0 (e.g., 400 V) of each of the first battery unit 102 and the second battery unit 104.

In the state shown in FIG. 5, if the first series connection switch 114 malfunctions and turns on for some reason, referring to FIG. 6, both terminals of the first battery unit 102 and the second battery unit 104 are shorted, and a short-circuit current flows as shown by the dashed arrow. As a result, referring to FIG. 7, the first parallel connection breaker 120 and the second parallel connection breaker 122 melt down. This causes both terminals of the first battery unit 102 and the second battery unit 104 to be opened, and the short-circuit state can be prevented from being maintained. Therefore, damage to the first battery unit 102 and the second battery unit 104, as well as the first parallel connection switch 110, the second parallel connection switch 112, and the first series connection switch 114 can be prevented. The first external connection terminal 132 and the second external connection terminal 134 are shorted by the first parallel connection switch 110, the second parallel connection switch 112, and the first series connection switch 114, and the voltage becomes 0V. Therefore, there is no risk of damage to the connected load 900.

(When charging)
When the first battery unit 102 and the second battery unit 104 are connected in parallel and charged, a DC power source is connected to the first external connection terminal 132 and the second external connection terminal 134 as a power source 904, and a charging current flows in the opposite direction to the arrow shown in FIG. 5. At this time, if the first series connection switch 114 malfunctions and turns on for some reason, both terminals of the first battery unit 102 and the second battery unit 104 are short-circuited as in FIG. 6, a short-circuit current flows, and the first parallel connection breaker 120 and the second parallel connection breaker 122 melt (see FIG. 7). As a result, both terminals of the first battery unit 102 and the second battery unit 104 are opened, and it is possible to prevent the short-circuit state from being maintained. During charging, referring to FIG. 8, the power source 904 is connected to the first external connection terminal 132 and the second external connection terminal 134. The first external connection terminal 132 and the second external connection terminal 134 are short-circuited by the first parallel connection switch 110, the second parallel connection switch 112, the first series connection switch 114, and the series connection breaker 124, thereby short-circuiting both terminals of the power source 904. As a result, a short-circuit current flows as shown by the arrow, and the series connection breaker 124 melts down, as shown in Fig. 9. This opens both terminals of the power source 904, making it possible to prevent the short-circuit state from being maintained and to prevent damage to the power source 904.

As described above, when the switching system 100 is installed in a vehicle and multiple vehicle batteries are connected in parallel, even if the series connection switch malfunctions and turns on, damage to the vehicle batteries can be avoided and external devices will not be affected.

Comparative Example
It is also possible to configure a switching system by arranging the parallel connection circuit breaker at a position different from that shown in Fig. 2. For example, referring to Fig. 10, a switching system 200 includes the first battery unit 102, the second battery unit 104, the first parallel connection switch 110, the second parallel connection switch 112, the first series connection switch 114, the series connection circuit breaker 124, the first parallel connection circuit breaker 202, and the second parallel connection circuit breaker 204, similar to the switching system 100. The switching system 200 is a system in which the first battery unit 102 and the second battery unit 104 in the switching system 100 of Fig. 2 are replaced by the first parallel connection circuit breaker 202 and the second parallel connection circuit breaker 204, respectively. The first parallel connection circuit breaker 202 and the second parallel connection circuit breaker 204 are arranged at a position different from that of the first battery unit 102 and the second battery unit 104. That is, the first parallel connection breaker 202 is directly connected in series with the first parallel connection switch 110 , and the second parallel connection breaker 204 is directly connected in series with the second parallel connection switch 112 .

Referring to FIG. 11, when the first battery unit 102 and the second battery unit 104 are connected in parallel, the first parallel connection switch 110 and the second parallel connection switch 112 are turned on and the first series connection switch 114 is turned off under the control of the control unit 130. When the first battery unit 102 and the second battery unit 104 are discharged, a current flows as shown by the dashed arrow, and power is supplied to the load 900 connected to the first external connection terminal 132 and the second external connection terminal 134. The voltage between the first external connection terminal 132 and the second external connection terminal 134 is the voltage V0 (e.g., 400 V) of each of the first battery unit 102 and the second battery unit 104.

11, if the first series connection switch 114 malfunctions and turns on for some reason, referring to FIG. 12, both terminals of the first battery unit 102 and the second battery unit 104 are shorted, and a short-circuit current flows as shown by the dashed arrow. As a result, referring to FIG. 13, the first parallel connection breaker 202 and the second parallel connection breaker 204 melt down. Meanwhile, the first battery unit 102 and the second battery unit 104 are connected in series by the first series connection switch 114, and the voltage between the first external connection terminal 132 and the second external connection terminal 134 becomes twice the voltage V0. As a result, a high voltage (e.g., 800V) twice as high as that when the first battery unit 102 and the second battery unit 104 are connected in parallel is applied to the load 900 connected to the first external connection terminal 132 and the second external connection terminal 134. When the switching system 100 is mounted on a vehicle, the device inside the vehicle corresponding to the load 900 is compatible with both the parallel connection and the series connection of the first battery unit 102 and the second battery unit 104, so no problems occur. However, if the device outside the vehicle (hereinafter referred to as the externally connected device) is compatible only with the parallel connection of the first battery unit 102 and the second battery unit 104, it will be damaged or otherwise affected by the application of high voltage.

In contrast, if the first battery unit 102 and the first parallel connection breaker 120 are directly connected in series, and the second battery unit 104 and the second parallel connection breaker 122 are directly connected in series, as shown in FIG. 2, the first external connection terminal 132 and the second external connection terminal 134 are short-circuited, as shown in FIG. 7. Therefore, as shown in FIG. 13, there is no high voltage between the first external connection terminal 132 and the second external connection terminal 134, and there is no effect such as damage to the connected load 900.

(First Modification)
In the switching system 100, the first battery unit 102 and the first parallel connection breaker 120 are connected in series, and the second battery unit 104 and the second parallel connection breaker 122 are connected in series, and the positions of the first parallel connection breaker 120 and the second parallel connection breaker 122 are not limited to the positions shown in FIG. 2. In the first modified example, referring to FIG. 14, the first parallel connection breaker 120 is disposed between the first battery unit 102 and the connection node of the first parallel connection switch 110 and the first series connection switch 114, and the second parallel connection breaker 122 is disposed between the second battery unit 104 and the connection node of the second parallel connection switch 112 and the first series connection switch 114. The other configurations in FIG. 14 are the same as those in FIG. 2. In FIG. 14, the elements denoted by the same reference numerals as those in FIG. 2 have the same functions as those described above, and therefore will not be described again and will be mainly described with respect to the differences.

In the configuration shown in FIG. 14, when the first battery unit 102 and the second battery unit 104 are connected in parallel (i.e., the first parallel connection switch 110 and the second parallel connection switch 112 are on), if the first series connection switch 114 is turned on due to a malfunction, it operates in the same manner as the configuration shown in FIG. 2. That is, both terminals of the first battery unit 102 and the second battery unit 104 are short-circuited, causing a short-circuit current to flow (see FIG. 6), and the first parallel connection circuit breaker 120 and the second parallel connection circuit breaker 122 melt (see FIG. 7). As a result, both terminals of the first battery unit 102 and the second battery unit 104 are opened, preventing the short-circuit state from being maintained.

14, the positions of the second battery unit 104 and the second parallel connection circuit breaker 122 may be interchanged, and the second battery unit 104 and the second parallel connection circuit breaker 122 may be connected as shown in FIG. 2. Also, in FIG. 14, the positions of the first battery unit 102 and the first parallel connection circuit breaker 120 may be interchanged, and the first battery unit 102 and the first parallel connection circuit breaker 120 may be connected as shown in FIG. 2. In either case, as in the configuration shown in FIG. 2, when the first battery unit 102 and the second battery unit 104 are connected in parallel, if the first series connection switch 114 is turned on due to a malfunction, both terminals of the first battery unit 102 and the second battery unit 104 are short-circuited, and a short-circuit current flows (see FIG. 6), and the first parallel connection circuit breaker 120 and the second parallel connection circuit breaker 122 melt (see FIG. 7). This opens both terminals of the first battery unit 102 and the second battery unit 104, preventing a short circuit from being maintained.

(Second Modification)
In the switching system 100, the position of the series-connected circuit breaker 124 is not limited to the position shown in Fig. 2. In a second modified example, referring to Fig. 15, the series-connected circuit breaker 124 is connected in series with the first series-connected switch 114. Other configurations in Fig. 15 are the same as those in Fig. 2. In Fig. 15, elements with the same reference numerals as those in Fig. 2 have the same functions as those described above, and therefore will not be described repeatedly.

In the configuration shown in FIG. 15, the first battery unit 102 and the second battery unit 104 are connected in parallel and can be charged by a DC power source connected to the first external connection terminal 132 and the second external connection terminal 134. At this time, if the first series connection switch 114 is turned on due to a malfunction, it operates in the same manner as the configuration shown in FIG. 2. That is, both terminals of the first battery unit 102 and the second battery unit 104 are short-circuited and a short-circuit current flows (see FIG. 6), and the first parallel connection circuit breaker 120 and the second parallel connection circuit breaker 122 melt (see FIG. 7). Therefore, both terminals of the first battery unit 102 and the second battery unit 104 are opened, and it is possible to prevent the short-circuit state from being maintained. At this time, the series connection circuit breaker 124 can also melt at the same time. By melting the series connection circuit breaker 124, it is possible to quickly prevent both terminals of the DC power source connected to the first external connection terminal 132 and the second external connection terminal 134 from being short-circuited, and it is possible to prevent the short-circuit current from flowing. This prevents damage to the DC power supply.

Before the series connection breaker 124 melts, the first parallel connection breaker 120 and the second parallel connection breaker 122 may melt. In that case, the first parallel connection switch 110, the second parallel connection switch 112, the first series connection switch 114, and the series connection breaker 124 short-circuit the first external connection terminal 132 and the second external connection terminal 134. As a result, both terminals of the DC power supply connected to the first external connection terminal 132 and the second external connection terminal 134 are short-circuited, and a short-circuit current flows (see FIG. 8). As a result, the series connection breaker 124 in FIG. 15 melts. As a result, the first external connection terminal 132 and the second external connection terminal 134 are opened, that is, the output terminals of the DC power supply connected to the first external connection terminal 132 and the second external connection terminal 134 are opened, and the short-circuit state is prevented from being maintained, and damage to the DC power supply is prevented.

Furthermore, when both terminals of the first battery unit 102 and the second battery unit 104 are short-circuited and a short-circuit current flows, the series connection circuit breaker 124 may melt before at least one of the first parallel connection circuit breaker 120 and the second parallel connection circuit breaker 122 melts. In that case, at least one of the first battery unit 102 and the second battery unit 104 is connected to the DC power source, so no problems will occur. Note that if the melting of the series connection circuit breaker 124 does not cause both the first parallel connection circuit breaker 120 and the second parallel connection circuit breaker 122 to melt, the parallel connection of the first battery unit 102 and the second battery unit 104 will be maintained, so no problems will occur.

The series connection circuit breaker 124 may be disposed on the electrical path (hereinafter, referred to as the line) within the dotted line shown in FIG. 15. The line within the dotted line is formed by melting the first parallel connection circuit breaker 120 and the second parallel connection circuit breaker 122 when the first parallel connection switch 110, the second parallel connection switch 112, and the first series connection switch 114 are in the on state. This line connects the first external connection terminal 132 and the second external connection terminal 134. The series connection circuit breaker 124 may be disposed at a position indicated by, for example, ellipse A. The series connection circuit breaker 124 may be connected in series with the first parallel connection switch 110 or the second parallel connection switch 112. That is, the series connection circuit breaker 124 may be disposed at any of the positions indicated by circle B. As a result, when the first battery unit 102 and the second battery unit 104 are connected in parallel, if the first series connection switch 114 malfunctions and turns on, the first external connection terminal 132 and the second external connection terminal 134 can be quickly opened, preventing damage to the DC power supply.

(Third Modification)
Although the above describes a configuration including two battery units, the present invention is not limited to this. The switching system may include three or more battery units. The switching system 300 according to the third modification uses three battery units connected in parallel or in series.

16, the switching system 300 includes the first battery unit 102, the second battery unit 104, the first parallel connection switch 110, the second parallel connection switch 112, the first series connection switch 114, the first parallel connection breaker 120, the second parallel connection breaker 122, the series connection breaker 124, the first external connection terminal 132, and the second external connection terminal 134. The switching system 300 further includes a third battery unit 302, a third parallel connection switch 304, a fourth parallel connection switch 306, a second series connection switch 308, a third parallel connection breaker 310, and a control unit 312. The switching system 300 is obtained by adding the third battery unit 302, the third parallel connection switch 304, the fourth parallel connection switch 306, the second series connection switch 308, and the third parallel connection breaker 310 to the switching system 100 of FIG. 2, and replacing the control unit 130 with the control unit 312. In FIG. 16, elements with the same reference numerals as in FIG. 2 have the same functions as described above, so we will not repeat the same explanation and will mainly explain the differences.

The third battery unit 302 is a unit composed of a rechargeable storage battery, and is a unit with the same specifications as the first battery unit 102 and the second battery unit 104. The first battery unit 102, the second battery unit 104, and the third battery unit 302 are, for example, 400V battery units.

The third parallel connection switch 304, the fourth parallel connection switch 306, and the second series connection switch 308, like the first parallel connection switch 110, etc., turn on or off both terminals of each switch under external control. Each of the third parallel connection switch 304, the fourth parallel connection switch 306, and the second series connection switch 308 is, for example, a relay, and may be a semiconductor element having a switching function such as an FET or an IGBT. The third parallel connection circuit breaker 310 connects both terminals of each switch with a low resistance value, and has the function of opening the connection between both terminals when a large current of a predetermined value or more flows. Here, the third parallel connection circuit breaker 310 is assumed to be a fuse like the first parallel connection circuit breaker 120, the second parallel connection circuit breaker 122, and the series connection circuit breaker 124.

The third battery unit 302 and the third parallel connection circuit breaker 310 are connected in series. The terminal (positive terminal) of the third battery unit 302 that is not connected to the third parallel connection circuit breaker 310 is connected to the fourth parallel connection switch 306. The terminal of the second parallel connection circuit breaker 122 that is not connected to the second battery unit 104 and the terminal of the third battery unit 302 that is not connected to the third parallel connection circuit breaker 310 are connected via the second series connection switch 308. The terminal of the second parallel connection circuit breaker 122 that is not connected to the second battery unit 104 is also connected to the third parallel connection switch 304. The terminal of the third parallel connection switch 304 that is not connected to the second parallel connection circuit breaker 122 is connected to the terminal of the third parallel connection circuit breaker 310 that is not connected to the third battery unit 302. The terminal of the fourth parallel connection switch 306 that is not connected to the third battery unit 302 is connected to the first external connection terminal 132 via the series connection circuit breaker 124. The terminal of the third parallel connection breaker 310 that is not connected to the third battery unit 302 is also connected to the second external connection terminal 134.

The control unit 312 outputs control signals in the same manner as the control unit 130, and controls the on/off operation of the first parallel connection switch 110, the second parallel connection switch 112, the first series connection switch 114, the third parallel connection switch 304, the fourth parallel connection switch 306, and the second series connection switch 308. As a result, the first battery unit 102, the second battery unit 104, and the third battery unit 302 are connected in parallel or in series. The first parallel connection switch 110, the second parallel connection switch 112, the third parallel connection switch 304, and the fourth parallel connection switch 306 are turned on, and the first series connection switch 114 and the second series connection switch 308 are turned off, so that the first battery unit 102, the second battery unit 104, and the third battery unit 302 are connected in parallel. The first parallel connection switch 110, the second parallel connection switch 112, the third parallel connection switch 304, and the fourth parallel connection switch 306 are turned off, and the first series connection switch 114 and the second series connection switch 308 are turned on, so that the first battery unit 102, the second battery unit 104, and the third battery unit 302 are connected in series.

(In the event of a malfunction)
17 and 18, a description will be given of an operation for avoiding damage due to a malfunction of the first series connection switch 114 when the first battery unit 102, the second battery unit 104, and the third battery unit 302 are connected in parallel. With reference to Fig. 17, when the first battery unit 102, the second battery unit 104, and the third battery unit 302 are connected in parallel, under the control of the first external connection terminal 132, the first parallel connection switch 110, the second parallel connection switch 112, the third parallel connection switch 304, and the fourth parallel connection switch 306 are turned on, and the first series connection switch 114 and the second series connection switch 308 are turned off.

(When discharging)
17, a current flows as shown by the dashed arrows, and power is supplied to the load 900 connected to the first external connection terminal 132 and the second external connection terminal 134. The voltage between the first external connection terminal 132 and the second external connection terminal 134 is the voltage V0 of each of the first battery unit 102, the second battery unit 104, and the third battery unit 302.

17, suppose that the first series connection switch 114 malfunctions and turns on for some reason. As a result, referring to FIG. 18, both terminals of the first battery unit 102, the second battery unit 104, and the third battery unit 302 are short-circuited, and a short-circuit current flows as shown by the dashed and solid arrows. The short-circuit current shown by the dashed arrow is the same as that in FIG. 6. Therefore, the first parallel connection circuit breaker 120 and the second parallel connection circuit breaker 122 melt down as in FIG. 7. As a result, both terminals of the first battery unit 102 and the second battery unit 104 are opened, and the short-circuit state is prevented from being maintained. As for the third battery unit 302, a short-circuit current flows as shown by the solid arrow. As a result, the third parallel connection circuit breaker 310 melts down, and both terminals of the third battery unit 302 are opened, and the short-circuit state is prevented from being maintained. Therefore, damage to the first battery unit 102, the second battery unit 104, and the third battery unit 302, as well as the first parallel connection switch 110, the second parallel connection switch 112, the first series connection switch 114, the third parallel connection switch 304, and the fourth parallel connection switch 306 can be avoided. The first external connection terminal 132 and the second external connection terminal 134 are short-circuited by the first parallel connection switch 110, the second parallel connection switch 112, the first series connection switch 114, and the series connection breaker 124, and the voltage becomes 0V. Therefore, the connected load 900 is not damaged.

17, if the second series connection switch 308 malfunctions and turns on for some reason, the first parallel connection circuit breaker 120, the second parallel connection circuit breaker 122, and the third parallel connection circuit breaker 310 will all melt down in the same manner as above. This causes both terminals of the first battery unit 102, the second battery unit 104, and the third battery unit 302 to be opened, preventing the short circuit state from being maintained. This prevents damage to the first battery unit 102, the second battery unit 104, and the third battery unit 302, as well as the first parallel connection switch 110, the second parallel connection switch 112, the first series connection switch 114, the third parallel connection switch 304, and the fourth parallel connection switch 306. The first external connection terminal 132 and the second external connection terminal 134 are short-circuited by the third parallel connection switch 304, the fourth parallel connection switch 306, the second series connection switch 308, and the series connection breaker 124, and the voltage becomes 0 V. Therefore, there is no damage to the connected load 900.

Also, in the state shown in FIG. 17, if the first series connection switch 114 and the second series connection switch 308 both malfunction and turn on for some reason, the first parallel connection circuit breaker 120, the second parallel connection circuit breaker 122, and the third parallel connection circuit breaker 310 will all melt down in the same manner as above. Also, the voltage between the first external connection terminal 132 and the second external connection terminal 134 will be 0V, and the connected load 900 will not be damaged.

(When charging)
When the first battery unit 102, the second battery unit 104, and the third battery unit 302 are connected in parallel and charged, a DC power supply is connected to the first external connection terminal 132 and the second external connection terminal 134. At this time, if the first series connection switch 114 malfunctions and turns on for some reason, both terminals of the first battery unit 102, the second battery unit 104, and the third battery unit 302 are short-circuited as in FIG. 18, a short-circuit current flows, and the first parallel connection circuit breaker 120, the second parallel connection circuit breaker 122, and the third parallel connection circuit breaker 310 melt. During charging, referring to FIG. 18, the first parallel connection switch 110, the second parallel connection switch 112, the first series connection switch 114, and the series connection circuit breaker 124 short-circuit the first external connection terminal 132 and the second external connection terminal 134. That is, the output terminals of the DC power supply are short-circuited. As a result, a short-circuit current flows, and the series connection circuit breaker 124 melts. This causes the output terminal of the DC power supply to be opened, preventing the short-circuit state from being maintained and preventing damage to the DC power supply.

The same applies when the first battery unit 102, the second battery unit 104, and the third battery unit 302 are connected in parallel and charged by a DC power source, and the second series connection switch 308 malfunctions and turns on for some reason. That is, the first parallel connection circuit breaker 120, the second parallel connection circuit breaker 122, and the third parallel connection circuit breaker 310 all melt down. Also, the third parallel connection switch 304, the fourth parallel connection switch 306, the second series connection switch 308, and the series connection circuit breaker 124 short-circuit the first external connection terminal 132 and the second external connection terminal 134, and the output terminal of the DC power source is short-circuited. As a result, a short-circuit current flows, and the series connection circuit breaker 124 melts down. This opens the output terminal of the DC power source, preventing the short-circuit state from being maintained, and preventing damage to the DC power source.

Also, when the first battery unit 102, the second battery unit 104, and the third battery unit 302 are connected in parallel and charged by a DC power source, if the first series connection switch 114 and the second series connection switch 308 malfunction for some reason and are both turned on, the same thing happens. That is, the first parallel connection circuit breaker 120, the second parallel connection circuit breaker 122, and the third parallel connection circuit breaker 310 all melt down. Also, the first external connection terminal 132 and the second external connection terminal 134 are short-circuited, and the output terminal of the DC power source is short-circuited. As a result, a short-circuit current flows and the series connection circuit breaker 124 melts down. This opens the output terminal of the DC power source, preventing the short-circuit state from being maintained and preventing damage to the DC power source.

The first battery unit 102 and the first parallel connection circuit breaker 120 may be connected in series, the second battery unit 104 and the second parallel connection circuit breaker 122 may be connected in series, and the third battery unit 302 and the third parallel connection circuit breaker 310 may be connected in series. As described above as the first modified example, in FIG. 16, the positions of the first battery unit 102 and the first parallel connection circuit breaker 120 may be swapped, the positions of the second battery unit 104 and the second parallel connection circuit breaker 122 may be swapped, or the positions of the third battery unit 302 and the third parallel connection circuit breaker 310 may be swapped.

Referring to FIG. 19, the series connection breaker 124 may be disposed at the position indicated by ellipse A. If the series connection breaker 124 is disposed at the position indicated by ellipse A, when the first battery unit 102, the second battery unit 104, and the third battery unit 302 are connected in parallel and being charged, it is possible to prevent the output terminals of the DC power supply from being short-circuited even if either the first series connection switch 114 or the second series connection switch 308 malfunctions and turns on.

Furthermore, as in the second modified example described above, the series connection circuit breaker 124 may be disposed anywhere on the line connecting the first external connection terminal 132 and the second external connection terminal 134, which is formed by melting the first parallel connection circuit breaker 120 and the second parallel connection circuit breaker 122 when the first parallel connection switch 110, the second parallel connection switch 112, and the first series connection switch 114 are in an on state. That is, referring to FIG. 19, the series connection circuit breaker 124 may be disposed at any of the positions indicated by the circle B. In this way, when the first battery unit 102, the second battery unit 104, and the third battery unit 302 are in a parallel connection state, if the first series connection switch 114 malfunctions and is turned on, the first external connection terminal 132 and the second external connection terminal 134 can be quickly opened, and damage to the DC power supply can be avoided. In addition, the series connection breaker 124 may be disposed on a line connecting the first external connection terminal 132 and the second external connection terminal 134, which is formed by melting the second parallel connection breaker 122 and the third parallel connection breaker 310 when the second parallel connection switch 112, the third parallel connection switch 304, the fourth parallel connection switch 306, and the second series connection switch 308 are in an on state. That is, referring to Fig. 19, the series connection breaker 124 may be disposed at any of the positions indicated by the circle C. In this way, when the first battery unit 102, the second battery unit 104, and the third battery unit 302 are in a parallel connection state, if the second series connection switch 308 malfunctions and is turned on, the first external connection terminal 132 and the second external connection terminal 134 can be quickly opened, and damage to the DC power supply can be avoided. Referring to FIG. 19, if a series-connected breaker (i.e., a fuse) is placed at the position of either circle B or circle C, the first external connection terminal 132 and the second external connection terminal 134 can be quickly opened even if either the first series-connected switch 114 or the fourth parallel-connected switch 306 is turned on due to a malfunction.

Although the above describes the case where two or three battery units are used, this is not limiting. When using four or more battery units and switching between their parallel connection or series connection, a switching system can be configured by arranging a parallel connection breaker and a series connection breaker in the same manner as described above. For example, a circuit configuration including four battery units can be achieved by adding a fourth battery unit, a parallel connection breaker, a series connection switch, and two parallel connection switches to the lower right side of the circuit in FIG. 16, similar to the change from FIG. 2 to FIG. 16.

From the configurations shown in Figures 2, 14, and 17, it can be seen that each of the multiple parallel-connected circuit breakers is arranged in a path through which current flows regardless of whether the multiple batteries are in a parallel-connected state or a series-connected state, and is connected in series with each of the multiple batteries in a one-to-one relationship. Note that the parallel-connected circuit breaker being connected in series with the battery in a one-to-one relationship does not only mean that the parallel-connected circuit breaker and the battery are directly connected in series, but also means that an element such as a resistor is connected in series between the parallel-connected circuit breaker and the battery.

In the above, a case has been described in which all the parallel-connected switches and the series-connected switches are relays, but this is not limiting. It is sufficient that at least one of the multiple parallel-connected switches and the one or more series-connected switches includes a relay. Also, in the above, a case has been described in which all the parallel-connected circuit breakers are fuses, but this is not limiting. It is sufficient that at least one of the multiple parallel-connected circuit breakers includes a fuse.

In the above, the case where fuses are used as the parallel-connected circuit breaker and the series-connected circuit breaker has been described, but this is not limiting. The parallel-connected circuit breaker and the series-connected circuit breaker may be any element capable of interrupting a large current such as a short-circuit current, and may be a circuit breaker or the like.

The present disclosure has been described above by explaining the embodiments, but the above-mentioned embodiments are merely examples, and the present disclosure is not limited to only the above-mentioned embodiments. The scope of the present disclosure is indicated by each claim in the scope of claims, taking into consideration the detailed description of the invention, and includes all modifications within the meaning and scope equivalent to the wording described therein.

100, 200, 300 Switching system 102 First battery unit 104 Second battery unit 110 First parallel connection switch 112 Second parallel connection switch 114 First

series connection switch

120, 202 First

parallel connection breaker

122, 204 Second parallel connection breaker 124

Series connection breaker

130, 312 Control unit 132 First external connection terminal 134 Second external connection terminal 140

Switching device

142, 144, 146, 148 Connection terminal 170 Vehicle 172 Power converter 174 Inverter 176 Motor 178 Auxiliary load 302 Third battery unit 304 Third parallel connection switch 306 Fourth parallel connection switch 308 Second series connection switch 310 Third parallel connection breaker 900 Load 902 External charger 904 Power source A Ovals B, C Circles BT1, BT2 Battery RY1, RY2, RY3, RY4, RY5, RY6, RY7 Relay

Claims

A plurality of batteries;
a plurality of parallel connection switches for connecting the plurality of batteries in parallel;
one or more series connection switches that connect the plurality of batteries in series;
a plurality of parallel-connected circuit breakers;
each of the plurality of parallel connection circuit breakers is disposed on a path through which a current flows regardless of whether the plurality of batteries are in the parallel connection state or the series connection state, and is connected in series with each of the plurality of batteries in a one-to-one relationship;
the plurality of batteries are brought into the parallel connection state or the series connection state by an on/off operation of the parallel connection switch and the series connection switch,
A switching system, wherein each of the plurality of parallel connection breakers, when opened, disconnects a corresponding one of the batteries from the parallel connection state.
a pair of external connection terminals for connecting the plurality of batteries to an external device;
2. The switching system according to claim 1, further comprising: a series-connected circuit breaker disposed on a line connecting the pair of external connection terminals to each other, the series-connected circuit breaker being formed by opening all of the parallel-connected circuit breakers when the parallel-connected switches are turned on and the series-connected switch is turned on.
The switching system according to claim 2, wherein the series-connected circuit breaker is connected in series with any one of the one or more series-connected switches.
The switching system according to any one of claims 1 to 3, further comprising a control unit that controls the on/off operation of each of the plurality of parallel-connected switches and the one or more series-connected switches.
The switching system according to any one of claims 1 to 4, wherein at least one of the plurality of parallel-connected switches and the one or more series-connected switches includes a relay.
The switching system according to any one of claims 1 to 5, wherein at least one of the multiple parallel-connected circuit breakers includes a fuse.
The switching system according to any one of claims 1 to 6, wherein the switching system is mounted on a vehicle.
A switching device disposed between a plurality of batteries and an external device,
a plurality of parallel connection switches that connect the plurality of batteries to the external device in a parallel connection state;
one or more series connection switches that connect the plurality of batteries to the external device in a series connection state;
a plurality of parallel-connected circuit breakers;
each of the plurality of parallel connection circuit breakers is disposed on a path through which a current flows regardless of whether the plurality of batteries are in the parallel connection state or the series connection state, and is connected in series with each of the plurality of batteries in a one-to-one relationship;
the parallel connection switch and the series connection switch are turned on and off to place the plurality of batteries in the parallel connection state or the series connection state;
A switching device, wherein each of the plurality of parallel connection breakers is opened to disconnect the corresponding battery from the parallel connection state.
a pair of external connection terminals for connecting the plurality of batteries to the external device;
9. The switching device according to claim 8, further comprising: a series-connected circuit breaker disposed on a line connecting the pair of external connection terminals to each other, the series-connected circuit breaker being formed by opening all of the parallel-connected circuit breakers when the parallel-connected switches are turned on and the series-connected switch is turned on.
The switching device according to claim 9, wherein the series-connected circuit breaker is connected in series with any one of the one or more series-connected switches.
The switching device according to any one of claims 8 to 10, further comprising a control unit that controls the on/off operation of each of the plurality of parallel-connected switches and the one or more series-connected switches.
The switching device according to any one of claims 8 to 11, wherein at least one of the plurality of parallel-connected switches and the one or more series-connected switches includes a relay.
The switching device according to any one of claims 8 to 12, wherein at least one of the multiple parallel-connected circuit breakers includes a fuse.
The switching device according to any one of claims 8 to 13, wherein the switching device is mounted on a vehicle.