Electric power supply device and apparatus

Abstract

The present invention prevents electric power that is being supplied to a step-down transformer from being cut off from at least one of a first battery and a second battery when changing the connection state of the first battery and the second battery.　An electric power supply device 5 comprises a first battery BT1 and a second battery BT2 that supply electric power to a first load L1, and a step-down transformer DR that steps down the voltage of at least one of the first battery BT1 and the second battery BT2 and supplies electric power to a second load L2, wherein: the first battery BT1 and the second battery BT2 are configured to be capable of being connected to the first load L1 and the step-down transformer DR in series, in parallel, or individually; and the electric power supply device furthermore comprises a first diode D1 that is provided between the positive electrode of the first battery BT1 and the positive electrode of the step-down transformer DR and is connected such that the direction from the positive electrode of the first battery BT1 toward the positive electrode of the step-down transformer DR is the forward direction thereof, a second diode D2 that is provided between the positive electrode of the second battery BT2 and the positive electrode of the step-down transformer DR and is connected such that the direction from the positive electrode of the second battery BT2 toward the positive electrode of the step-down transformer DR is the forward direction thereof, and a third diode D3 that is provided between the negative electrode of the first battery BT1 and the negative electrode of the step-down transformer DR and is connected such that the direction from the negative electrode of the step-down transformer DR toward the negative electrode of the first battery BT1 is the forward direction thereof.

Description

Power supply devices and equipment

[0001] The present invention relates to a power supply device and a device.

[0002] Conventionally, there has been a need to connect multiple batteries in series, parallel, and independently according to user requirements. For example, Patent Document 1 discloses that when switching between the series connection and parallel connection of multiple batteries, a period during which the switch for series connection and the switch for parallel connection are simultaneously turned on is not set in order to prevent short-circuiting of the battery output destination. In addition, in recent years, efforts to realize a low-carbon or carbon-free society have been intensifying, and CO2 emissions in vehicles have also been increasing. ２ Research and development into electrification technologies is being conducted to reduce emissions and improve energy efficiency.

[0003] International Publication No. 2018 / 1233991

[0004] However, with the technology described in Patent Document 1, there is a possibility that power will not be supplied to electrical equipment such as lighting fixtures when the series connection switch and the parallel connection switch are simultaneously OFF. Furthermore, in technologies related to electrification, it is an issue to appropriately switch between series connection, parallel connection, and single connection of multiple batteries. The present application aims to solve the above issue by achieving appropriate switching between series connection, parallel connection, and single connection of multiple batteries, thereby contributing to improved energy efficiency.

[0005] One aspect of the present invention is a power supply device comprising a first battery and a second battery that supply power to a first load, and a step-down converter that steps down the voltage of at least one of the first battery and the second battery to supply power to a second load, wherein the first battery and the second battery are configured to be connectable to the first load and the step-down converter in series, in parallel, or individually, and the power supply device comprises: a first diode that is arranged between the positive electrode of the first battery and the positive electrode of the step-down converter and is connected so that the forward direction is from the positive electrode of the first battery to the positive electrode of the step-down converter; a second diode that is arranged between the positive electrode of the second battery and the positive electrode of the step-down converter and is connected so that the forward direction is from the positive electrode of the second battery to the positive electrode of the step-down converter; and a third diode that is arranged between the negative electrode of the first battery and the negative electrode of the step-down converter and is connected so that the forward direction is from the negative electrode of the step-down converter to the negative electrode of the first battery.

[0006] According to the present invention, when the connection state of the first battery and the second battery with the step-down converter is switched between series connection, parallel connection, and single connection, it is possible to prevent the power supplied from the battery to the step-down converter from being interrupted.

[0007] Fig. 1 is a diagram showing an example of the configuration of a motorcycle according to this embodiment. Fig. 2 is a diagram showing an example of the configuration of a power supply device according to this embodiment. Fig. 3 is a diagram showing an example of a state in which a first battery and a second battery are connected in series. Fig. 4 is a diagram showing an example of a state in which the first battery and the second battery are connected in parallel. Fig. 5 is a diagram showing another example of a state in which the first battery and the second battery are connected in parallel. Fig. 6 is a diagram showing an example of a state in which the first battery is connected alone. Fig. 7 is a diagram showing an example of a state in which the second battery is connected alone.

[0008] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0009] [1. Vehicle Configuration] First, the configuration of a motorcycle 1 according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing an example of the configuration of a motorcycle according to this embodiment. The motorcycle 1 is an electric motorcycle that is one form of a straddle-type electric vehicle. The motorcycle 1 includes a front wheel 3 that is a steerable wheel and a rear wheel 4 that is a drive wheel. The front wheel 3 is rotatably supported by a pair of left and right front forks 6. The front wheel 3 can be steered by a handlebar 2. The motorcycle 1 corresponds to an example of "equipment."

[0010] The rear wheel 4 is supported at the rear of a swing arm 20 that is swingably supported on the body frame F. The motorcycle 1 is a unit swinging type motorcycle. The swing arm 20 is equipped with a motor MT that drives the motorcycle 1 and a speed reduction mechanism (not shown) that reduces the driving force of the motor MT and transmits it to the rear wheel axle. A rear fender that covers the upper rear part of the rear wheel 4 is supported at the rear end of the swing arm 20 via a fender support arm 40. The lower end of a rear cushion 7, which is a rear suspension component, is connected to the fender support arm 40.

[0011] The body frame F includes a head pipe 12 at its front end. The head pipe 12 steers the front wheel 3 via a steering stem 11 and left and right front forks 6. A headlight HL (not shown) is fixed to the head pipe 12. The body frame F also includes a pair of left and right upper frames 13, a pair of left and right lower frames 14, and a pair of left and right seat frames 15. The upper frames 13 extend diagonally downward and rearward from approximately the center of the head pipe 12 in the vertical direction. The lower frames 14 extend downward from a lower region of the head pipe 12, then extend toward the rear of the vehicle body, and then extend upward from their rear ends at a slight rearward incline. The seat frame 15 extends diagonally upward and rearward from approximately the center of the upper frames 13 in the longitudinal direction. The lower frames 14 are connected by a middle frame 16. The rear regions of the lower frames 14 and the seat frame 15 are connected by a support frame 17.

[0012] The motor MT is held by the main arm of the swing arm 20 and is disposed to the left of the rear wheel 4. The motor MT is an inner rotor type motor and includes an inner rotor having a motor output shaft and a stator. The motor MT is disposed in the rear region of the main arm of the swing arm 20. The motor MT corresponds to an example of a "first load."

[0013] The first battery BT1 and the second battery BT2 each supply power to the motor MT. The first battery BT1 and the second battery BT2 are arranged in the front-to-rear direction inside a battery storage device 64 provided below the seat. The first battery BT1 and the second battery BT2 are each formed in a substantially rectangular parallelepiped shape and have the same configuration. The first battery BT1 and the second battery BT2 are, for example, lithium-ion batteries that serve as chargeable and dischargeable energy storage. The first battery BT1 and the second battery BT2 are configured to be detachable from the vehicle body. In other words, the first battery BT1 and the second battery BT2 are configured to be detachable from the battery storage device 64. The battery storage device 64 corresponds to an example of a "vehicle body."

[0014] [2. Configuration of the Power Supply Device] Next, the configuration of the power supply device 5 will be described with reference to FIG. 2 . FIG. 2 is a diagram illustrating an example of the configuration of the power supply device 5. The power supply device 5 is mounted on the motorcycle 1. As shown in FIG. 2 , the power supply device 5 includes a first battery BT1 and a second battery BT2. The power supply device 5 supplies power from the first battery BT1 and the second battery BT2 to a first load L1. The first load L1 is, for example, a power control unit (PCU) 51 or a motor MT. The PCU 51 converts DC power supplied from at least one of the first battery BT1 and the second battery BT2 into three-phase AC power based on a control signal input from an electronic control unit (ECU) (described later), and supplies the power to drive the motor MT, which is a three-phase AC motor. The PCU 51 is a so-called inverter. The PCU 51 includes input sections corresponding to the positive and negative DC power input from at least one of the first battery BT1 and the second battery BT2, and output sections corresponding to the three-phase power supplied to the motor MT. The PCU 51 and the motor MT are examples of a "first load."

[0015] The step-down converter DR steps down the voltage of at least one of the first battery BT1 and the second battery BT2 and supplies power to an auxiliary device L2 (not shown). The step-down converter DR has input sections corresponding to the positive and negative DC power input from at least one of the first battery BT1 and the second battery BT2, and output sections corresponding to the positive and negative DC power output to the auxiliary device L2. The auxiliary device L2 includes a headlight HL that emits light ahead of the motorcycle 1. The step-down converter DR is configured, for example, with a linear regulator. The linear regulator steps down the voltage using a voltage-dividing resistor. The auxiliary device L2 is an example of a "second load." The headlight HL is an example of a "lighting device."

[0016] In this embodiment, the step-down converter DR is a linear regulator, but the embodiment is not limited to this. The step-down converter DR may be, for example, a switching regulator.

[0017] The ECU includes a processor 511 such as a CPU (Central Processing Unit) and a memory 512 such as a ROM (Read Only Memory).

[0018] The memory 512 is a storage device that nonvolatilely stores programs and data executed by the processor 511. The memory 512 is configured with a magnetic storage device, a semiconductor storage element such as a flash ROM, or other types of nonvolatile storage devices. The memory 512 may also include a random access memory (RAM) that forms a work area for the processor 511. The memory 512 stores data processed by the processor 511 and control programs executed by the processor 511. The processor 511 may be configured with a single processor, or may be configured with multiple processors functioning as the processor 511.

[0019] The ECU switches each of the first switch S1, the second switch S2, and the third switch S3 between a connected state and a disconnected state based on a user operation. The user operation, for example, instructs a series connection or a parallel connection of the first battery BT1 and the second battery. The user operation also instructs a standalone connection of the first battery BT1 or a standalone connection of the second battery. The power supply device 5 includes, for example, an operation mechanism (not shown) that accepts user operations. The ECU accepts user operations via the operation mechanism. The ECU corresponds to an example of a "controller."

[0020] 2 , a first battery BT1 and a second battery BT2 supply power to a motor MT, which is a first load L1, via a PCU 51. In the following description, for convenience, the positive electrode of the PCU 51 will be referred to as the positive electrode of the first load L1 or the positive electrode of the motor MT, and the negative electrode of the PCU 51 will be referred to as the negative electrode of the first load L1 or the negative electrode of the motor MT.

[0021] The power supply device 5 also includes a first diode D1, a second diode D2, and a third diode D3. The first diode D1 is disposed between the positive electrode of the first battery BT1 and the positive electrode of the step-down converter DR, and is connected so that the forward direction is from the positive electrode of the first battery BT1 to the positive electrode of the step-down converter DR.

[0022] The second diode D2 is disposed between the positive electrode of the second battery BT2 and the positive electrode of the step-down converter DR, and is connected so that the forward direction is from the positive electrode of the second battery BT2 to the positive electrode of the step-down converter DR. The third diode D3 is disposed between the negative electrode of the first battery BT1 and the negative electrode of the step-down converter DR, and is connected so that the forward direction is from the negative electrode of the step-down converter DR to the negative electrode of the first battery BT1.

[0023] The power supply device 5 also includes a first switch S1, a second switch S2, and a third switch S3. The ECU switches the first switch S1 between a connected state and a disconnected state. The ECU also switches the second switch S2 between a connected state and a disconnected state. The ECU also switches the third switch S3 between a connected state and a disconnected state. Each of the first switch S1, the second switch S2, and the third switch S3 is formed by, for example, a contactor. In the following description, the "connected state" is referred to as ON, and the "disconnected state" is referred to as OFF.

[0024] The first switch S1 is disposed between the negative electrode of the first battery BT1 and the positive electrode of the second battery BT2, and switches the negative electrode of the first battery BT1 and the positive electrode of the second battery BT2 ON or OFF. In other words, the ECU turns the negative electrode of the first battery BT1 and the positive electrode of the second battery BT2 ON by turning the first switch S1 ON. The ECU also turns the negative electrode of the first battery BT1 and the positive electrode of the second battery BT2 OFF by turning the first switch S1 OFF.

[0025] The second switch S2 is disposed between the positive electrode of the PCU 51 and the positive electrode of the second battery BT2 and switches the positive electrode of the PCU 51 and the positive electrode of the second battery BT2 ON or OFF. In other words, the PCU 51 turns the positive electrode of the PCU 51 and the positive electrode of the second battery BT2 ON by turning the second switch S2 ON. The ECU turns the positive electrode of the PCU 51 and the positive electrode of the second battery BT2 OFF by turning the second switch S2 OFF.

[0026] The third switch S3 is disposed between the negative electrode of the PCU 51 and the negative electrode of the first battery BT1, and switches the negative electrode of the PCU 51 and the negative electrode of the first battery BT1 ON or OFF. In other words, the ECU turns the negative electrode of the PCU 51 and the negative electrode of the first battery BT1 ON by turning the third switch S3 ON. The ECU also turns the negative electrode of the PCU 51 and the negative electrode of the first battery BT1 OFF by turning the third switch S3 OFF.

[0027] 2, the positive electrode of the second battery BT2 is connected to the first switch S1 at the first connection terminal T1. The negative electrode of the first battery BT1 is connected to the first switch S1 at the second connection terminal T2. The second diode D2 is disposed between the first connection terminal T1 and the positive electrode of the step-down converter DR, and is connected so that the forward direction is from the first connection terminal T1 to the positive electrode of the step-down converter DR. The third diode D3 is disposed between the second connection terminal T2 and the negative electrode of the step-down converter DR, and is connected so that the forward direction is from the negative electrode of the step-down converter DR to the second connection terminal T2.

[0028] The first battery BT1 and the second battery BT2 are connectable in series, in parallel, or independently to the PCU 51 and the step-down converter DR. The connection states of the first battery BT1 and the second battery BT2 with the PCU 51 and the step-down converter DR will be described below with reference to Figures 3 to 6.

[0029] 3. Operation of the Power Supply Device Next, a case where the first battery BT1 and the second battery BT2 are connected in series to the PCU 51 and the step-down converter DR will be described with reference to Fig. 3. Fig. 3 is a diagram showing an example of a state in which the first battery BT1 and the second battery BT2 are connected in series. In the following description, for convenience, the state in which the first battery BT1 and the second battery BT2 are connected in series to the PCU 51 and the step-down converter DR will be referred to as a first state ST1.

[0030] In the first state ST1, the ECU turns the first switch S1 ON, the second switch S2 OFF, and the third switch S3 OFF. In Fig. 3, the diagonal lines of the rectangular marks corresponding to the second switch S2 and the third switch S3 are solid lines, indicating that the second switch S2 and the third switch S3 are OFF. In addition, the diagonal line of the rectangular mark corresponding to the first switch S1 is not drawn, indicating that the first switch S1 is ON.

[0031] By turning on the first switch S1, turning off the second switch S2, and turning off the third switch S3, the first battery BT1 and the second battery BT2 are connected in series to the PCU 51 and the step-down converter DR. For example, current flows through the PCU 51 as shown by the dashed line. That is, current flows from the negative electrode of the PCU 51 to the negative electrode of the second battery BT2. Current also flows from the positive electrode of the second battery BT2 to the negative electrode of the second battery BT2 via the first connection terminal T1, the first switch S1, and the second connection terminal T2 in this order. Current also flows from the positive electrode of the first battery BT1 to the positive electrode of the PCU 51.

[0032] For example, current flows through the step-down converter DR as shown by the dashed line. That is, current flows from the negative electrode of the step-down converter DR to the negative electrode of the second battery BT2. Current also flows from the positive electrode of the second battery BT2 sequentially via the first connection terminal T1, the first switch S1, and the second connection terminal T2 to the negative electrode of the second battery BT2. Current also flows from the positive electrode of the first battery BT1 to the positive electrode of the step-down converter DR via the first diode D1.

[0033] Next, with reference to FIGS. 4 and 5 , a case where the first battery BT1 and the second battery BT2 are connected in parallel to the motor MT and the step-down converter DR will be described. In the following description, for convenience, the state where the first battery BT1 and the second battery BT2 are connected in parallel to the PCU 51 and the step-down converter DR will be referred to as a second state ST2. FIG. 4 is a diagram showing an example of a state where the first battery BT1 and the second battery BT2 are connected in parallel. FIG. 4 illustrates a case where the battery voltage of the first battery BT1 is higher than the battery voltage of the second battery BT2. In other words, a case where the SOC (State of Charge) of the first battery BT1 is higher than the SOC of the second battery BT2 will be described. The state shown in FIG. 4 will be referred to as a second state ST21. FIG. 5 is a diagram showing another example of a state where the first battery BT1 and the second battery BT2 are connected in parallel. 5 illustrates a case where the battery voltage of the first battery BT1 is lower than the battery voltage of the second battery BT2. In other words, a case where the SOC of the first battery BT1 is lower than the SOC of the second battery BT2 is illustrated. The state illustrated in FIG. 5 is referred to as a second state ST22. That is, the second state ST2 includes the second state ST21 illustrated in FIG. 4 and the second state ST22 illustrated in FIG. 4.

[0034] As shown in Figures 4 and 5, in the second state ST2, the ECU turns the first switch S1 OFF, the second switch S2 ON, and the third switch S3 ON. In Figure 4, the diagonal line of the rectangular mark corresponding to the first switch S1 is drawn with a solid line, indicating that the first switch S1 is OFF. Furthermore, the diagonal line of the rectangular mark corresponding to each of the second switch S2 and the third switch S3 is not drawn, indicating that each of the second switch S2 and the third switch S3 is ON. By turning the first switch S1 OFF, the second switch S2 ON, and the third switch S3 ON, the first battery BT1 and the second battery BT2 are connected in parallel to the PCU 51 and the step-down converter DR.

[0035] As shown in Figure 4, current flows through the PCU 51 as indicated by the dashed line. That is, current flows from the negative electrode of the PCU 51 to the negative electrode of the first battery BT1 via the third switch S3. Current also flows from the positive electrode of the first battery BT1 to the positive electrode of the PCU 51. Current is also supplied to the load from the second battery BT2. Current flows from the negative electrode of the PCU 51 to the negative electrode of the second battery BT2. Current also flows from the positive electrode of the second battery BT2 to the positive electrode of the PCU 51 via the second switch S2.

[0036] Furthermore, for example, current flows through the step-down converter DR as shown by the dashed line. That is, current flows from the negative electrode of the step-down converter DR, sequentially via the third diode D3 and the second connection terminal T2, toward the negative electrode of the first battery BT1. Current also flows from the positive electrode of the first battery BT1, via the first diode D1, toward the positive electrode of the step-down converter DR. Thus, when the battery voltage of the first battery BT1 is higher than the battery voltage of the second battery BT2, only the power of the first battery BT1 is supplied to the step-down converter DR. In this case, the power consumption of the first battery BT1 is greater than the power consumption of the second battery BT2. Therefore, the SoCs of the first battery BT1 and the second battery BT2 can be equalized without providing a separate battery discharge circuit or the like.

[0037] As shown in Figure 5, when the battery voltage of the first battery BT1 is lower than the battery voltage of the second battery BT2, current flows through the PCU 51 as indicated by the dashed line. That is, current flows from the negative electrode of the PCU 51 to the negative electrode of the second battery BT2. Current also flows from the positive electrode of the second battery BT2 to the positive electrode of the PCU 51 via the first connection terminal T1 and the second switch S2. Current is also supplied to the load from the first battery BT1. Current flows from the negative electrode of the PCU 51 to the negative electrode of the first battery BT1 via the third switch S3. Current also flows from the positive electrode of the first battery BT1 to the positive electrode of the PCU 51.

[0038] Furthermore, for example, current flows through the step-down converter DR as shown by the dashed line. That is, current flows from the negative electrode of the step-down converter DR to the negative electrode of the second battery BT2. Current also flows from the positive electrode of the second battery BT2 to the positive electrode of the step-down converter DR via the first connection terminal T1 and the second diode D2. Thus, when the battery voltage of the first battery BT1 is lower than the battery voltage of the second battery BT2, only the power of the second battery BT2 is supplied to the step-down converter DR and the PCU 51. In this case, the power consumption of the second battery BT2 is greater than the power consumption of the first battery BT1. Therefore, the SoCs of the first battery BT1 and the second battery BT2 can be equalized without providing a separate battery discharge circuit or the like.

[0039] Between the first state ST1 shown in Fig. 3 and the second state ST2 shown in Fig. 4 and Fig. 5, the only factor that changes the path of the current flowing through the step-down converter DR is the ON / OFF of the first switch S1. In other words, the ON / OFF of the second switch S2 and the ON / OFF of the third switch S3 do not affect the change in the path of the current flowing through the step-down converter DR.

[0040] Therefore, for example, when the first switch S1 changes from ON to OFF in a transition from the first state ST1 to the second state ST2, the path of the current flowing through the step-down converter DR changes from the path shown by the dashed line in Fig. 3 to the path shown by the dashed line in Fig. 4 or 5. Also, for example, when the second state ST2 changes to the first state ST1, when the first switch S1 changes from OFF to ON, the path of the current flowing through the step-down converter DR changes from the path shown by the dashed line in Fig. 4 or 5 to the path shown by the dashed line in Fig. 3. Therefore, it is possible to prevent the power supplied to the step-down converter DR from at least one of the first battery BT1 and the second battery BT2 from being interrupted.

[0041] The step-down converter DR is connected to the first battery BT1 and the second battery BT2 via the following three paths: a path connecting the positive electrode of the first battery BT1 to the positive electrode of the step-down converter DR, a path connecting the first connection terminal T1 to the positive electrode of the step-down converter DR, and a path connecting the second connection terminal T2 to the negative electrode of the step-down converter DR. A first diode D1, a second diode D2, and a third diode D3 are connected to each of these three paths. Therefore, the direction of current flow in the three paths is properly regulated. This prevents current from flowing in an inappropriate direction through the step-down converter DR.

[0042] Next, a case where the first battery BT1 or the second battery BT2 is connected singly to the PCU 51 and the step-down converter DR will be described with reference to Figures 6 and 7. Figure 6 is a diagram showing an example of a state in which the first battery BT1 is connected singly to the PCU 51 and the step-down converter DR. In the following description, for convenience, the state in which the first battery BT1 is connected singly to the PCU 51 and the step-down converter DR will be referred to as a third state ST3.

[0043] In the third state ST3, the ECU turns the first switch S1 OFF, the second switch S2 OFF, and the third switch S3 ON. In Fig. 6, the diagonal lines of the rectangular marks corresponding to the first switch S1 and the second switch S2 are solid lines, indicating that the first switch S1 and the second switch S2 are OFF. In addition, the diagonal line of the rectangular mark corresponding to the third switch S3 is not drawn, indicating that the third switch S3 is ON.

[0044] By turning the first switch S1 OFF, the second switch S2 OFF, and the third switch S3 ON, the first battery BT1 is connected independently to the PCU 51 and the step-down converter DR. For example, current flows through the PCU 51 as shown by the dashed line. That is, current flows from the negative terminal of the PCU 51 to the negative terminal of the first battery BT1, sequentially via the third switch S3 and the second connection terminal T2. Current also flows from the positive terminal of the first battery BT1 to the positive terminal of the PCU 51.

[0045] For example, current flows through the step-down converter DR as shown by the dashed line. That is, current flows from the negative electrode of the step-down converter DR to the negative electrode of the first battery BT1 via the third diode D3 and the second connection terminal T2. Current also flows from the positive electrode of the first battery BT1 to the positive electrode of the step-down converter DR via the first diode D1.

[0046] 7 is a diagram showing an example of a state in which the second battery BT2 is connected alone to the PCU 51 and the step-down converter DR. In the following description, for convenience, the state in which the second battery BT2 is connected alone to the PCU 51 and the step-down converter DR will be referred to as a fourth state ST4.

[0047] In the fourth state ST4, the ECU turns the first switch S1 OFF, the second switch S2 ON, and the third switch S3 OFF. In Fig. 7, the diagonal lines of the rectangular marks corresponding to the first switch S1 and the third switch S3 are solid lines, indicating that the first switch S1 and the third switch S3 are OFF. Furthermore, the diagonal line of the rectangular mark corresponding to the second switch S2 is not drawn, indicating that the second switch S2 is ON.

[0048] By turning the first switch S1 OFF, the second switch S2 ON, and the third switch S3 OFF, the second battery BT2 is connected independently to the PCU 51 and the step-down converter DR. For example, current flows through the PCU 51 as shown by the dashed line. That is, current flows from the negative electrode of the PCU 51 to the negative electrode of the second battery BT2. Current also flows from the positive electrode of the second battery BT2 to the positive electrode of the PCU 51 via the first connection terminal T1 and the second switch S2 in this order.

[0049] For example, a current flows through the step-down converter DR as shown by the dashed line. That is, a current flows from the negative electrode of the step-down converter DR to the negative electrode of the second battery BT2. A current also flows from the positive electrode of the second battery BT2 to the positive electrode of the step-down converter DR via the first connection terminal T1 and the second diode D2 in this order.

[0050] [4. Configuration and Effects] As described above, the power supply device 5 according to this embodiment is a power supply device 5 including a first battery BT1 and a second battery BT2 that supply power to a first load L1, and a step-down converter DR that steps down the voltage of at least one of the first battery BT1 and the second battery BT2 and supplies the power to the second load L2, wherein the first battery BT1 and the second battery BT2 are configured to be connectable in series, in parallel, or singly to the first load L1 and the step-down converter DR, and the step-down converter DR is disposed between the positive electrode of the first battery BT1 and the positive electrode of the step-down converter DR, The circuit comprises a first diode D1 connected so that the forward direction is from the positive electrode of the first battery BT1 to the positive electrode of the step-down converter DR, a second diode D2 arranged between the positive electrode of the second battery BT2 and the positive electrode of the step-down converter DR and connected so that the forward direction is from the positive electrode of the second battery BT2 to the positive electrode of the step-down converter DR, and a third diode D3 arranged between the negative electrode of the first battery BT1 and the negative electrode of the step-down converter DR and connected so that the forward direction is from the negative electrode of the step-down converter DR to the negative electrode of the first battery BT1.

[0051] According to this configuration, when the connection state of the first battery BT1 and the second battery BT2 is changed, it is possible to prevent the power supplied to the step-down converter DR from at least one of the first battery BT1 and the second battery BT2 from being cut off.

[0052] The power supply device 5 further includes a first switch S1 disposed between the negative electrode of the first battery BT1 and the positive electrode of the second battery BT2, for switching the negative electrode of the first battery BT1 and the positive electrode of the second battery BT2 between a connected state and a disconnected state; a second switch S2 disposed between the positive electrode of the first load L1 and the positive electrode of the second battery BT2, for switching the positive electrode of the first load L1 and the positive electrode of the second battery BT2 between a connected state and a disconnected state; and a second switch S3 disposed between the negative electrode of the first load L1 and the negative electrode of the first battery BT1, for switching the negative electrode of the first load L1 and the negative electrode of the first battery BT1 between a connected state and a disconnected state. and a third switch S3 that switches between a connected state and a disconnected state, the second diode D2 is arranged between the first connection terminal T1, which connects the positive electrode of the second battery BT2 and the first switch S1, and the positive electrode of the step-down converter DR, and is connected so that the direction from the first connection terminal T1 to the positive electrode of the step-down converter DR is the forward direction, and the third diode D3 is arranged between the second connection terminal T2, which connects the negative electrode of the first battery BT1 and the first switch S1, and the negative electrode of the step-down converter DR, and is connected so that the direction from the negative electrode of the step-down converter DR to the second connection terminal T2 is the forward direction.

[0053] With this configuration, when the first battery BT1 and the second battery BT2 are connected in parallel to the first load L1 or the second load L2, only the power of the battery with the higher voltage between the first battery BT1 and the second battery BT2 can be supplied to the second load L2. Therefore, the SoCs of the first battery BT1 and the second battery BT2 can be equalized without providing a separate battery discharge circuit or the like.

[0054] The power supply device 5 also includes an ECU that switches each of the first switch S1, the second switch S2, and the third switch S3 between a connected state and a disconnected state based on an operation by a user.

[0055] With this configuration, the connection state of the first battery BT1 and the second battery BT2 can be changed to a connection state desired by the user. Note that the connection state of the first battery BT1 and the second battery BT2 includes a state in which the first battery BT1 and the second battery BT2 are connected in series or parallel, a state in which the first battery BT1 is connected alone, and a state in which the second battery BT2 is connected alone.

[0056] The device 1 according to this embodiment is a power supply device 5 including a first battery BT1 and a second battery BT2 that supply power to a first load L1, and a step-down converter DR that steps down the voltage of at least one of the first battery BT1 and the second battery BT2 and supplies power to the second load L2, in which the first battery BT1 and the second battery BT2 are configured to be connectable in series, in parallel, or singly to the first load L1 and the step-down converter DR, and the first battery BT1 is disposed between the positive electrode of the first battery BT1 and the positive electrode of the step-down converter DR, and the first battery BT2 is connected to the first load L1 and the step-down converter DR in series, in parallel, or singly. The circuit comprises a first diode D1 connected so that the forward direction is from the positive electrode of T1 to the positive electrode of the step-down converter DR, a second diode D2 arranged between the positive electrode of the second battery BT2 and the positive electrode of the step-down converter DR and connected so that the forward direction is from the positive electrode of the second battery BT2 to the positive electrode of the step-down converter DR, and a third diode D3 arranged between the negative electrode of the first battery BT1 and the negative electrode of the step-down converter DR and connected so that the forward direction is from the negative electrode of the step-down converter DR to the negative electrode of the first battery BT1.

[0057] This configuration provides the same effects as the power supply device 5 according to the present embodiment.

[0058] The device 1 also includes a first switch S1 disposed between the negative electrode of the first battery BT1 and the positive electrode of the second battery BT2, for switching the negative electrode of the first battery BT1 and the positive electrode of the second battery BT2 between a connected state and a disconnected state; a second switch S2 disposed between the positive electrode of the first load L1 and the positive electrode of the second battery BT2, for switching the positive electrode of the first load L1 and the positive electrode of the second battery BT2 between a connected state and a disconnected state; and a second switch S3 disposed between the negative electrode of the first load L1 and the negative electrode of the first battery BT1, for connecting the negative electrode of the first load L1 and the negative electrode of the first battery BT1. and a third switch S3 that switches between an on state and a cut-off state, the second diode D2 is arranged between the first connection terminal T1, which connects the positive electrode of the second battery BT2 and the first switch S1, and the positive electrode of the step-down converter DR, and is connected so that the forward direction is from the first connection terminal T1 to the positive electrode of the step-down converter DR, and the third diode D3 is arranged between the second connection terminal T2, which connects the negative electrode of the first battery BT1 and the first switch S1, and the negative electrode of the step-down converter DR, and is connected so that the forward direction is from the negative electrode of the step-down converter DR to the second connection terminal T2.

[0059] According to this configuration, the connection state of the first battery BT1 and the second battery BT2 can be changed by switching each of the first switch S1, the second switch S2, and the third switch S3 between a connected state and a disconnected state. Note that the connection state of the first battery BT1 and the second battery BT2 includes a state in which the first battery BT1 and the second battery BT2 are connected in series or parallel, a state in which the first battery BT1 is connected alone, and a state in which the second battery BT2 is connected alone. Furthermore, when changing the connection state of the first battery BT1 and the second battery BT2, it is possible to prevent the power supplied to the step-down converter DR from at least one of the first battery BT1 and the second battery BT2 from being interrupted.

[0060] The device 1 also includes an ECU that switches each of the first switch S1, the second switch S2, and the third switch S3 between a connected state and a disconnected state based on an operation by a user.

[0061] With this configuration, the connection state of the first battery BT1 and the second battery BT2 can be changed to a connection state desired by the user. Note that the connection state of the first battery BT1 and the second battery BT2 includes a state in which the first battery BT1 and the second battery BT2 are connected in series or parallel, a state in which the first battery BT1 is connected alone, and a state in which the second battery BT2 is connected alone.

[0062] In the device 1, each of the first battery BT1 and the second battery BT2 is configured to be detachable from the vehicle body (for example, the battery storage device 64).

[0063] According to this configuration, even when the device 1 is used in a state where there is a difference in the SoC between the first battery BT1 and the second battery BT2, when the first battery BT1 and the second battery BT2 are connected in parallel to the first load L1 or the second load L2, the SoC of the first battery BT1 and the second battery BT2 can be equalized without providing a separate battery discharge circuit or the like.

[0064] 5. Other Embodiments The present invention is not limited to the configurations of the above-described embodiments, and can be implemented in various forms without departing from the spirit of the present invention.

[0065] For example, in the above embodiment, the case where the "equipment" is a motorcycle 1 is described, but the embodiment is not limited to this. The "equipment" may be, for example, a four-wheeled passenger car or a four-wheeled large vehicle. Furthermore, the "equipment" may be, for example, a work vehicle such as a tractor. Furthermore, the "equipment" is not limited to a "vehicle" and may be an electric power shovel or a floodlight.

[0066] Although the above embodiment describes a case where the "controller" is configured by an ECU, the embodiment is not limited to this. The "controller" may be configured by, for example, an ASIC (Application Specific Integrated Circuit), an FPGA (Field-Programmable Gate Array), or the like. Furthermore, the "controller" may be configured by, for example, an SoC (System-on-a-Chip) or an MCU (Micro Control Unit).

[0067] 6. Configurations Supported by the Above-described Embodiments The above-described embodiments support the following configurations.

[0068] (Configuration 1) A power supply device comprising: a first battery and a second battery that supply power to a first load; and a step-down converter that steps down the voltage of at least one of the first battery and the second battery to supply power to a second load, wherein the first battery and the second battery are configured to be connectable to the first load and the step-down converter in series, in parallel, or individually; a first diode that is arranged between the positive electrode of the first battery and the positive electrode of the step-down converter and is connected so that the forward direction is from the positive electrode of the first battery to the positive electrode of the step-down converter; a second diode that is arranged between the positive electrode of the second battery and the positive electrode of the step-down converter and is connected so that the forward direction is from the positive electrode of the second battery to the positive electrode of the step-down converter; and a third diode that is arranged between the negative electrode of the first battery and the negative electrode of the step-down converter and is connected so that the forward direction is from the negative electrode of the step-down converter to the negative electrode of the first battery.

[0069] According to the power supply device of configuration 1, when the connection state of the first battery and the second battery is changed, it is possible to prevent the power supplied from at least one of the first battery and the second battery to the step-down converter from being cut off, and it is also possible to prevent current from flowing in an inappropriate direction from at least one of the first battery and the second battery to the step-down converter.

[0070] (Configuration 2) A first switch is disposed between the negative electrode of the first battery and the positive electrode of the second battery, and switches the negative electrode of the first battery and the positive electrode of the second battery between a connected state and a disconnected state; a second switch is disposed between the positive electrode of the first load and the positive electrode of the second battery, and switches the positive electrode of the first load and the positive electrode of the second battery between a connected state and a disconnected state; and a third switch is disposed between the negative electrode of the first load and the negative electrode of the first battery, and switches the negative electrode of the first load and the negative electrode of the first battery between a connected state and a disconnected state. and a third switch connected to the positive electrode of the step-down converter, wherein the second diode is arranged between a first connection terminal to which the positive electrode of the second battery and the first switch are connected and the positive electrode of the step-down converter, and is connected so that the direction from the first connection terminal to the positive electrode of the step-down converter is the forward direction, and the third diode is arranged between a second connection terminal to which the negative electrode of the first battery and the first switch are connected and the negative electrode of the step-down converter, and is connected so that the direction from the negative electrode of the step-down converter to the second connection terminal is the forward direction.

[0071] According to the power supply device of configuration 2, when the first battery and the second battery are connected in parallel to the first load or the second load, only the power of the battery with the higher voltage of the first battery or the second battery can be supplied to the second load. Therefore, the SoCs of the first battery and the second battery can be equalized without providing a separate battery discharge circuit or the like.

[0072] (Configuration 3) A power supply device according to configuration 1 or 2, further comprising a control unit that switches each of the first switch, the second switch, and the third switch to a connected state or a disconnected state based on an operation by a user.

[0073] According to the power supply device of configuration 3, the connection state of the first battery and the second battery can be changed to a connection state desired by the user. Note that the connection state of the first battery and the second battery includes a state in which the first battery and the second battery are connected in series or parallel, a state in which the first battery is connected alone, and a state in which the second battery is connected alone.

[0074] (Configuration 4) A device comprising a first battery and a second battery that supply power to a first load, and a step-down converter that reduces the voltage of at least one of the first battery and the second battery to supply power to a second load, wherein the first battery and the second battery are configured to be connectable to the first load in series, in parallel, or individually, and the device comprises: a first diode that is arranged between the positive electrode of the first battery and the positive electrode of the step-down converter and is connected so that the forward direction is from the positive electrode of the first battery to the positive electrode of the step-down converter; a second diode that is arranged between the positive electrode of the second battery and the positive electrode of the step-down converter and is connected so that the forward direction is from the positive electrode of the second battery to the positive electrode of the step-down converter; and a third diode that is arranged between the negative electrode of the first battery and the negative electrode of the step-down converter and is connected so that the forward direction is from the negative electrode of the step-down converter to the negative electrode of the first battery.

[0075] The device of the fourth configuration provides the same effects as the power supply device of the first configuration.

[0076] (Configuration 5) A first switch is disposed between the negative electrode of the first battery and the positive electrode of the second battery, and switches the negative electrode of the first battery and the positive electrode of the second battery between a connected state and a disconnected state; a second switch is disposed between the positive electrode of the first load and the positive electrode of the second battery, and switches the positive electrode of the first load and the positive electrode of the second battery between a connected state and a disconnected state; and a third switch is disposed between the negative electrode of the first load and the negative electrode of the first battery, and switches the negative electrode of the first load and the negative electrode of the first battery between a connected state and a disconnected state. the second diode is arranged between a first connection terminal to which the positive electrode of the second battery and the first switch are connected and the positive electrode of the step-down device, and is connected so that the direction from the first connection terminal to the positive electrode of the step-down device is the forward direction; and the third diode is arranged between a second connection terminal to which the negative electrode of the first battery and the first switch are connected and the negative electrode of the step-down device, and is connected so that the direction from the negative electrode of the step-down device to the second connection terminal is the forward direction.

[0077] The device of the fifth configuration provides the same effects as the power supply device of the second configuration.

[0078] (Configuration 6) The device described in Configuration 5, further comprising a control unit that switches each of the first switch, the second switch, and the third switch to a connected state or a disconnected state based on an operation from a user.

[0079] The device of the sixth configuration provides the same effects as the power supply device of the third configuration.

[0080] (Configuration 7) The device according to any one of Configurations 4 to 6, wherein each of the first battery and the second battery is configured to be detachable from the device body.

[0081] According to the device of configuration 7, even when a vehicle is used with a difference in SoC between the first battery and the second battery, when the first battery and the second battery are connected in parallel to the first load or the second load, the SoC of the first battery and the second battery can be equalized without providing a separate battery discharge circuit or the like.

[0082] REFERENCE SIGNS LIST 1 Motorcycle (equipment) 5 Power supply device 51 PCU (first load) 64 Battery storage device (vehicle body) BT1 First battery BT2 Second battery D1 First diode D2 Second diode D3 Third diode DR Step-down converter HL Headlight (second load, lighting device) L1 First load L2 Auxiliary device (second load) MT Motor (first load) S1 First switch S2 Second switch S3 Third switch ST1 First state ST2, ST21, ST22 Second state ST3 Third state ST4 Fourth state T1 First connection terminal T2 Second connection terminal

Claims

1. A power supply device comprising: a first battery and a second battery that supply power to a first load; and a step-down converter that steps down the voltage of at least one of the first battery and the second battery to supply power to a second load, wherein the first battery and the second battery are configured to be connectable to the first load and the step-down converter in series, in parallel, or individually; a first diode that is arranged between the positive electrode of the first battery and the positive electrode of the step-down converter and is connected so that the forward direction is from the positive electrode of the first battery to the positive electrode of the step-down converter; a second diode that is arranged between the positive electrode of the second battery and the positive electrode of the step-down converter and is connected so that the forward direction is from the positive electrode of the second battery to the positive electrode of the step-down converter; and a third diode that is arranged between the negative electrode of the first battery and the negative electrode of the step-down converter and is connected so that the forward direction is from the negative electrode of the step-down converter to the negative electrode of the first battery.

2. A first switch is disposed between the negative electrode of the first battery and the positive electrode of the second battery, and switches the negative electrode of the first battery and the positive electrode of the second battery between a connected state and a disconnected state; a second switch is disposed between the positive electrode of the first load and the positive electrode of the second battery, and switches the positive electrode of the first load and the positive electrode of the second battery between a connected state and a disconnected state; and a third switch is disposed between the negative electrode of the first load and the negative electrode of the first battery, and switches the negative electrode of the first load and the negative electrode of the first battery between a connected state and a disconnected state; and the second diode is disposed between a first connection terminal that connects the positive electrode of the second battery and the first switch, and the positive electrode of the step-down device, and is connected so that the direction from the first connection terminal toward the positive electrode of the step-down device is the forward direction; 2. The power supply device according to claim 1, wherein the third diode is arranged between a second connection terminal to which the negative electrode of the first battery and the first switch are connected and the negative electrode of the step-down converter, and is connected so that the direction from the negative electrode of the step-down converter to the second connection terminal is the forward direction.

3. The power supply device according to claim 2, further comprising a control unit that switches each of the first switch, the second switch, and the third switch between a connected state and a disconnected state based on an operation by a user.

4. A device comprising: a first battery and a second battery that supply power to a first load; and a step-down converter that steps down the voltage of at least one of the first battery and the second battery to supply power to a second load, wherein the first battery and the second battery are configured to be connectable to the first load in series, in parallel, or individually; a first diode that is arranged between the positive electrode of the first battery and the positive electrode of the step-down converter and is connected so that the forward direction is from the positive electrode of the first battery to the positive electrode of the step-down converter; a second diode that is arranged between the positive electrode of the second battery and the positive electrode of the step-down converter and is connected so that the forward direction is from the positive electrode of the second battery to the positive electrode of the step-down converter; and a third diode that is arranged between the negative electrode of the first battery and the negative electrode of the step-down converter and is connected so that the forward direction is from the negative electrode of the step-down converter to the negative electrode of the first battery.

5. A first switch is disposed between the negative electrode of the first battery and the positive electrode of the second battery, and switches the negative electrode of the first battery and the positive electrode of the second battery between a connected state and a disconnected state; a second switch is disposed between the positive electrode of the first load and the positive electrode of the second battery, and switches the positive electrode of the first load and the positive electrode of the second battery between a connected state and a disconnected state; and a third switch is disposed between the negative electrode of the first load and the negative electrode of the first battery, and switches the negative electrode of the first load and the negative electrode of the first battery between a connected state and a disconnected state; and the second diode is disposed between a first connection terminal that connects the positive electrode of the second battery and the first switch and the positive electrode of the step-down device, and is connected so that the direction from the first connection terminal toward the positive electrode of the step-down device is the forward direction; The device according to claim 4, wherein the third diode is arranged between a second connection terminal to which the negative electrode of the first battery and the first switch are connected and the negative electrode of the step-down converter, and is connected such that a direction from the negative electrode of the step-down converter to the second connection terminal is a forward direction.

6. The device according to claim 5, further comprising a control unit that switches each of the first switch, the second switch, and the third switch between a connected state and a disconnected state based on an operation by a user.

7. The device according to any one of claims 4 to 6, wherein each of the first battery and the second battery is configured to be detachable from the device body.

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