Electricity storage system

Abstract

A power storage system capable of efficiently charging according to the voltage state of a charging device and reducing the manufacturing cost. A power storage system (1) is provided with: a storage battery that can be charged at 400 V, 800 V, and 1200 V; a three-phase motor that is driven by the power supplied from the battery and that has three-phase coils connected to a neutral point; an inverter (5) connected to power supply circuits (11P, 11N) of the battery and the three-phase motor; and DC power supply circuits (13P, 13N) connected to a power transmission path between the inverter and the storage battery. A DC power supply circuit (13P) on the positive electrode side has a branch circuit (14) that is connected to any one of the three-phase coils at a connection section (34) via a first semiconductor switch (QC / CC). A second semiconductor switch (VS / CB) is provided between the connection section (34) and the inverter for any one of the three-phase coils.

Description

Technical Field

[0001] The present invention relates to a power storage system. Background Art

[0002] In recent years, in order to ensure that more people can obtain affordable, reliable, and sustainable modern energy, active research and development have been carried out on charging and power supply in mobile bodies equipped with secondary batteries to contribute to energy efficiency.

[0003] Regarding charging and power supply in mobile bodies equipped with secondary batteries, there are two types of charging devices such as charging piles: a 400V class with a maximum voltage of 500V and an 800V class with a maximum voltage of 1000V. When the mobile body only supports the 400V class of charging devices, it cannot enjoy the fast charging performance of the 800V class of charging devices.

[0004] When the mobile body supports both 400V class and 800V class of charging devices, generally, when charging with the 400V class of charging devices, a voltage converter is used to boost the voltage to 800V for charging, or when charging with the 800V class of charging devices, a voltage converter is used to step down the voltage to 400V for charging. However, if a charging voltage converter is used during charging, the efficiency deteriorates.

[0005] Regarding this problem, it is known that a mobile body can charge using both 400V class and 800V class of charging devices without using a charging voltage converter by switching the connection method of battery modules (for example, Patent Document 1, Patent Document 2).

[0006] Prior Art Documents

[0007] Patent Documents

[0008] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2019-080474

[0009] Patent Document 2: Japanese Unexamined Patent Application Publication No. 2020-150618 Summary of the Invention

[0010] Problems to be Solved by the Invention

[0011] On the other hand, there are also two types of auxiliary machines used in mobile bodies: those driven at 400V class and those driven at 800V class. In a mobile body that switches the connection method of battery modules, when driving a 400V class auxiliary machine during charging with an 800V class charging device, or when driving an 800V class auxiliary machine during charging with a 400V class charging device, etc., generally, a voltage converter for the auxiliary machine is used for voltage conversion. However, the voltage converter for the auxiliary machine is expensive, increasing the manufacturing cost.

[0012] In addition, in recent years, in order to reduce the burden on the power distribution section and terminals of the charging system of a moving body, a charging method with a higher voltage and lower current has been proposed. In a 1200V-class charging device with a maximum voltage of 1500V, the burden on the power distribution section and terminals of the charging system can be reduced compared to 400V-class and 800V-class charging devices. For example, when the output of the charging device is 320kW, theoretically, a current of 800A flows through a 400V-class charging device, and a current of 400A flows through an 800V-class charging device. On the other hand, in a 1200V-class charging device, the current can be reduced to 265A.

[0013] Thus, in a moving body that can be charged even with charging devices having different upper limit voltages by switching the connection mode of battery modules, a power storage system that can operate an auxiliary machine without using an expensive voltage converter for the auxiliary machine is desired.

[0014] The present invention provides a power storage system that can efficiently charge according to the voltage state of a charging device and can reduce manufacturing costs.

[0015] Solution to the problem

[0016] A power storage system according to an aspect of the present invention includes:

[0017] A storage battery having a switch group and a plurality of power storage sections, wherein the switch group can switch between a first voltage state in which charging can be performed at a first voltage, a second voltage state in which charging can be performed at a second voltage higher than the first voltage, and a third voltage state in which charging can be performed at a third voltage higher than the second voltage by switching the connection state of the plurality of power storage sections;

[0018] A three-phase motor having three-phase coils connected to a neutral point and driven by power supplied from the storage battery;

[0019] An inverter connected to the power transmission path between the storage battery and the three-phase motor; and

[0020] A DC power supply circuit connected to a first connection portion located on the power transmission path between the inverter and the storage battery,

[0021] The DC power supply circuit on the positive electrode side has a branch circuit that is connected to any one of the three-phase coils at a second connection portion via a first semiconductor switch,

[0022] For any one of the three-phase coils, a second semiconductor switch is provided between the second connection portion and the inverter.

[0023] Effect of the invention

[0024] According to the present invention, charging can be efficiently performed based on the voltage state of a charging device, and the manufacturing cost can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 FIG. is a diagram showing the structure of the power storage system 1 according to the first embodiment.

[0026] Figure 2 FIG. is a diagram showing the structure of the storage battery 2.

[0027] Figure 3 FIG. is a diagram showing Figure 1 the structure of the inverter 5 of the power storage system 1.

[0028] Figure 4 FIG. is a diagram showing the first voltage state (400V start state) of the storage battery 2.

[0029] Figure 5 FIG. is a diagram showing the second voltage state (800V start state) of the storage battery 2.

[0030] Figure 6 FIG. is a diagram showing the third voltage state (1200V start state) of the storage battery 2.

[0031] Figure 7 FIG. is a diagram showing the flow of current when an electric vehicle equipped with the power storage system 1 according to the first embodiment is running.

[0032] Figure 8 FIG. is a diagram showing the flow of current when an electric vehicle equipped with the power storage system 1 according to the first embodiment is charged at the first voltage (400V).

[0033] Figure 9 FIG. is a diagram for explaining the boosting operation of the inverter 5.

[0034] Figure 10 FIG. is a diagram for explaining the boosting operation of the inverter 5.

[0035] Figure 11 FIG. is a diagram showing the flow of current when an electric vehicle equipped with the power storage system 1 according to the first embodiment is charged at the second voltage (800V).

[0036] Figure 12 FIG. is a diagram showing the flow of current when an electric vehicle equipped with the power storage system 1 according to the first embodiment is charged at the third voltage (1200V).

[0037] Figure 13 FIG. is a diagram for explaining the bucking operation of the inverter 5.

[0038] Figure 14 FIG. is a diagram for explaining the bucking operation of the inverter 5.

[0039] Figure 15 It is a table summarizing the states of switches and contactors in each mode of the power storage system 1 of the first embodiment.

[0040] Figure 16 It is a flowchart showing the control process of the power storage system 1.

[0041] Figure 17 It is a diagram showing the structure of the power storage system 1 of the second embodiment.

[0042] Figure 18 It is a diagram showing the flow of current when the electric vehicle equipped with the power storage system 1 of the second embodiment is running.

[0043] Figure 19 It is a diagram showing the flow of current when the electric vehicle equipped with the power storage system 1 of the second embodiment is charged with the first voltage (400V).

[0044] Figure 20 It is a diagram showing the flow of current when the electric vehicle equipped with the power storage system 1 of the second embodiment is charged with the second voltage (800V).

[0045] Figure 21 It is a diagram showing the flow of current when the electric vehicle equipped with the power storage system 1 of the second embodiment is charged with the third voltage (1200V).

[0046] Figure 22 It is a table summarizing the states of each mode of the power storage system 1 of the second embodiment.

[0047] Description of reference numerals:

[0048] 1 Power storage system

[0049] 2 Storage battery

[0050] 3 Three-phase motor

[0051] 5 Inverter

[0052] 10 Control unit

[0053] 14 Branch circuit

[0054] 21 Power storage section

[0055] 31 Neutral point

[0056] 34 Connection part (second connection part)

[0057] 41 First switch section (switch group)

[0058] 43 Third switch section (switch section)

[0059] VS / C_B Second semiconductor switch (second semiconductor switch)

[0060] QC / C_C First semiconductor switch (first semiconductor switch). Detailed implementation manners

[0061] Hereinafter, each implementation manner of the present invention will be described with reference to the accompanying drawings. First, with reference to Figures 1 to 16 The first implementation manner of the present invention will be described.

[0062] [First implementation manner]

[0063] Figure 1 The power storage system 1 of the first implementation manner shown is mounted on an electric vehicle such as an electric car. The electric vehicle mounted with the power storage system 1 supports charging devices of 400V class with an upper limit voltage of 500V, 800V class with an upper limit voltage of 1000V, and 1200V class with an upper limit voltage of 1500V. It can not only quickly charge the storage battery 2 with charging voltages of 400V, 800V, and 1200V, but also drive the three-phase motor 3 and auxiliary machines 4 with a base voltage of 800V. In addition, the charging voltages of 400V, 800V, and 1200V are only examples, and the power storage system 1 is not limited thereto, as long as it can be charged by charging devices with different upper limit voltages.

[0064] Specifically, as Figure 1 shown, the power storage system 1 includes a storage battery 2, a three-phase motor 3, auxiliary machines 4, an inverter 5 (INV), a DC-DC converter 6, power supply circuits 11P, 11N, auxiliary machine drive circuits 12P, 12N, DC power supply circuits 13P, 13N, a branch circuit 14, and a control unit 10. In Figure 1 it, reference numeral 7 is a drive unit, and reference numeral 8 is an auxiliary machine unit.

[0065] As Figure 1 and Figure 2 shown, the storage battery 2 includes six power storage parts 21, a first switch part 41, a first contactor M / C, a pre-charge contactor P / C, a first resistor R1, a current sensor IS, and a current breaker FUSE.

[0066] The power storage parts 21 are respectively storage battery modules capable of performing charge and discharge at 400V.

[0067] The first contactor M / C is disposed at the end on the positive electrode side of the storage battery 2 and functions as a main switch for connecting and disconnecting the connection with the outside (power supply circuit 11P) of the storage battery 2.

[0068] As Figure 2As shown, the first switch unit 41 includes, for example, eight switches (S / C_A, S / C_B, S / C_C, S / C_D, S / C_E, S / C_F, S / C_G, S / C_H). The eight switches are an example of a switch group that switches the connection states of the six power storage units 21 of the storage battery 2. In the first voltage state where the six power storage units 21 shown in Figure 4 are connected in parallel, the storage battery 2 can be charged and discharged at 400V. Hereinafter, this first voltage state in which the storage battery 2 can be charged and discharged at 400V is also referred to as the 400V start state.

[0069] In addition, in the Figure 5 second voltage state where two sets of three power storage units 21 connected in parallel as shown are connected in series, the storage battery 2 can be charged and discharged at 800V. Hereinafter, this second voltage state in which the storage battery 2 can be charged and discharged at 800V is also referred to as the 800V start state. Further, in the Figure 6 third voltage state where three sets of two power storage units 21 connected in parallel as shown are connected in series, the storage battery 2 can be charged and discharged at 1200V. Hereinafter, this third voltage state in which the storage battery 2 can be charged and discharged at 1200V is also referred to as the 1200V start state.

[0070] Return Figure 1 , the pre-charge contactor P / C is arranged in series with the first resistor R1 and in parallel with the first contactor M / C. When pre-charging the smoothing capacitor C1, the pre-charge contactor P / C is turned on before the first contactor M / C is turned on, thereby protecting the first contactor M / C from excessive inrush current. The pre-charge contactor P / C maintains an open state except when pre-charging the smoothing capacitor C1.

[0071] The current sensor IS is arranged between the first contactor M / C and the six power storage units 21 to measure the current.

[0072] The current breaker FUSE is arranged at the negative electrode side end of the storage battery 2 and cuts off the connection with the outside (power supply circuit 11N) of the storage battery 2 in case of an abnormality. In the power storage system 1 of the present embodiment, the current breaker FUSE is composed of a high-temperature fuse that can actively cut off the current according to an electrical signal. In case of an abnormality (such as a vehicle collision or a short circuit inside the storage battery 2), the current breaker FUSE performs a breaking operation, and all the contactors inside the storage battery 2 are turned off (opened).

[0073] The three-phase motor 3 includes three-phase coils 32U, 32V, and 32W whose one end sides are connected at the neutral point 31, and is rotationally driven by the power supplied from the storage battery 2 via the inverter 5. The three-phase motor 3 of the present embodiment includes a U-phase terminal 33U, a V-phase terminal 33V, and a W-phase terminal 33W connected to the other end sides of the coils 32U, 32V, and 32W. The U-phase terminal 33U, the V-phase terminal 33V, and the W-phase terminal 33W are connected to the inverter 5. In addition, the other end side of any one of the coils 32U, 32V, and 32W is connected to the branch circuit 14 at the connection portion 34. In the present embodiment, among the three-phase coils 32U, 32V, and 32W, the coil 32U is connected to the branch circuit 14 at the connection portion 34 located between the U-phase terminal 33U and the inverter 5.

[0074] For the U-phase coil 32U to which the branch circuit 14 is connected, a fourth switching portion 44 is provided between the connection portion 34 and the inverter 5. The fourth switching portion 44 is constituted by a second semiconductor switch VS / C_B. The second semiconductor switch VS / C_B connects and disconnects the circuit between the connection portion 34 and the inverter 5. The second semiconductor switch VS / C_B is constituted by, for example, a MOSFET, and the MOSFET is arranged such that the body diode allows current to flow back from the inverter 5 side to the three-phase motor 3 side. Therefore, when the second semiconductor switch VS / C_B is in the off state, the flow of current from the connection portion 34 side to the inverter 5 side is cut off, and current is allowed to flow from the inverter 5 side to the connection portion 34 side. In addition, the second semiconductor switch VS / C_B may be any semiconductor switch capable of high-frequency on / off, and may be constituted by a bipolar transistor, an IGBT, etc. instead of a MOSFET.

[0075] The inverter 5 converts the DC power supplied from the storage battery 2 into three-phase AC power by switching a plurality of switching elements, and rotationally drives the three-phase motor 3. As Figure 3 shown, the inverter 5 includes: a first DC circuit 51 having a first high-side switch TH1, a first low-side switch TL1, and a first node P1 connecting the first high-side switch TH1 and the first low-side switch TL1 in series; a second DC circuit 52 having a second high-side switch TH2, a second low-side switch TL2, and a second node P2 connecting the second high-side switch TH2 and the second low-side switch TL2 in series; a third DC circuit 53 having a third high-side switch TH3, a third low-side switch TL3, and a third node P3 connecting the third high-side switch TH3 and the third low-side switch TL3 in series. The high-side switch side ends of the first DC circuit 51, the second DC circuit 52, and the third DC circuit 53 are connected in parallel to the positive power supply circuit 11P, and the low-side switch side ends are connected in parallel to the negative power supply circuit 11N.

[0076] Further, the first node P1 is connected to the coil 32U by being connected to the U-phase terminal 33U, the second node P2 is connected to the coil 32V by being connected to the V-phase terminal 33V, and the third node P3 is connected to the coil 32W by being connected to the W-phase terminal 33W. In addition, the switches TH1, TL1, TH2, TL2, TH3, TL3 are constituted by MOSFETs, for example, and are controlled to be opened and closed by adjusting the gate voltage by the control unit 10.

[0077] Diodes operating as freewheeling diodes are respectively connected in parallel with the switches TH1, TL1, TH2, TL2, TH3, TL3. The purpose of providing the freewheeling diodes is to cause the current flowing backward from the motor 24 side to flow back (regenerate) to the power supply 11 side when the switches TH1, TL1, TH2, TL2, TH3, TL3 are turned off, thereby preventing damage to the switching elements. That is, the inverter 5 allows the current to flow from the three-phase motor 3 side to the battery 2 side regardless of whether the gate is on or off, and allows the current to flow from the battery 2 side to the three-phase motor 3 side only when the gate is on.

[0078] As will be described in detail later, when the power storage system 1 supplies a voltage of 400V from the branch circuit 14 to the connection portion 34, the three-phase motor 3 can function as a part of the boost circuit by switching the switches TH1, TL1, TH2, TL2, TH3, TL3. In addition, when a voltage of 1200V is supplied from the branch circuit 14 to the connection portion 34, the three-phase motor 3 can function as a part of the buck circuit by switching the first semiconductor switch QC / C_C (second switch unit 42) and the second semiconductor switch VS / C_B (fourth switch unit 44) described later and the switches TH1, TL1, TH2, TL2, TH3, TL3.

[0079] The auxiliary machine 4 is a high-voltage-driven in-vehicle device that can be driven by DC power from the battery 2 and an external power supply, and includes, for example, an electric compressor for air conditioning, a heater, etc. The auxiliary machine 4 is connected to the battery 2 via the auxiliary machine drive circuits 12P, 12N, the third switch unit 43, and the power supply circuits 11P, 11N. The auxiliary machine 4 of the present embodiment operates at a base voltage of 800V.

[0080] The DC-DC converter 6 steps down the DC power from the battery 2 and the external power supply to drive a low-voltage-driven in-vehicle device.

[0081] The power supply circuits 11P and 11N are composed of a positive and a negative pair, connecting the battery 2 to the inverter 5 (three-phase motor 3). First connection parts 111P and 111N, which are connection parts to the DC power supply circuits 13P and 13N, are provided in the power supply circuits 11P and 11N. Second connection parts 112P and 112N, which are connection parts to the auxiliary machine drive circuits 12P and 12N (auxiliary machine 4), are provided on the side of the inverter 5 relative to the first connection parts 111P and 111N. Additionally, a third switch part 43 for turning the circuit on and off is provided in the power supply circuit 11P on the positive electrode side between the connection part 112P to the auxiliary machine drive circuit 12P and the connection part 111P to the DC power supply circuit 13P. The third switch part 43 is composed of a second contactor VS / C_A. The second contactor VS / C_A is, for example, an electromagnetic contactor.

[0082] Furthermore, a first voltage sensor V_PIN, a smoothing capacitor C1, and a second resistor R2 are provided on the side of the inverter 5 in the power supply circuits 11P and 11N. The first voltage sensor V_PIN, the smoothing capacitor C1, and the second resistor R2 are respectively provided on the circuit connecting the power supply circuit 11P on the positive electrode side to the power supply circuit 11N on the negative electrode side. In addition, the second resistor R2 is provided to discharge the smoothing capacitor C1 when the circuit is cut off.

[0083] The DC power supply circuits 13P and 13N are composed of a positive and a negative pair. Charging terminals 131P and 131N capable of connecting an external power source such as a charging device are provided at one end, and the other end is connected to the power supply circuits 11P and 11N via the first connection parts 111P and 111N. A third contactor QC / C_A and a fourth contactor QC / C_B for turning on and off each circuit are provided in the DC power supply circuits 13P and 13N. Additionally, a second voltage sensor V_BAT is provided at a position on the side of the first connection parts 111P and 111N relative to the third contactor QC / C_A and the fourth contactor QC / C_B. A third voltage sensor V_QC is provided at a position on the side of the charging terminals 131P and 131N relative to the third contactor QC / C_A and the fourth contactor QC / C_B.

[0084] The branch circuit 14 branches off in the DC power supply circuit 13P on the positive electrode side at a position closer to the connection part 111P than the third contactor QC / C_A and the second voltage sensor V_BAT, and is connected to any one of the coils of the three-phase motor 3 via the connection part 34. A second switch part 42 for turning the circuit on and off is provided in the middle part of the branch circuit 14. The second switch part 42 is constituted by a first semiconductor switch QC / C_C. In the first semiconductor switch QC / C_C, MOSFETs are connected in series in such a manner that the body diodes are reverse-biased. Therefore, when the first semiconductor switch QC / C_C is in the off state, the current flowing through the branch circuit 14 is cut off by the first semiconductor switch QC / C_C. In addition, the first semiconductor switch QC / C_C may be any semiconductor switch capable of high-frequency on / off, and may be constituted by a bipolar transistor, an IGBT, etc. instead of a MOSFET.

[0085] The control unit 10 is, for example, a vehicle ECU, and controls the driving and charging of the power storage system 1. More specifically, the control unit 10 performs on / off control (including PWM control) of the first to fourth switch parts 41 to 44 and each contactor, control of the DC-DC converter 6, and control of the inverter 5.

[0086] Next, Figures 7 to 14 the operation of the power storage system 1 will be described.

[0087] Figure 7 It is a diagram showing the flow of current when the electric vehicle equipped with the power storage system 1 of the first embodiment is running (800V running).

[0088] As described above, the electric vehicle equipped with the power storage system 1 drives the three-phase motor 3 and the auxiliary machine 4 with a base voltage of 800V, and the storage battery 2 is controlled to be Figure 5 the 800V start state shown during running. In addition, the control unit 10 turns on the first contactor M / C, the second contactor VS / C_A (the third switch part 43), and the second semiconductor switch VS / C_B (the fourth switch part 44), and turns off the third contactor QC / C_A, the fourth contactor QC / C_B, and the first semiconductor switch QC / C_C (the second switch part 42). The circuit mode at this time is called the first mode.

[0089] In this first mode, since a voltage of 800V is supplied from the storage battery 2 to the three-phase motor 3 via the inverter 5, the electric vehicle can run. At this time, the auxiliary machine 4 is driven by the 800V voltage supplied from the storage battery 2 via the power supply circuits 11P, 11N and the auxiliary machine drive circuits 12P, 12N.

[0090] Figure 8This is a diagram showing the flow of current during the first voltage charging (400V charging) of an electric vehicle equipped with the energy storage system 1 of the first embodiment.

[0091] When charging with a 400V-class charging device, the storage battery 2 is controlled to be Figure 4 in the 400V start state shown. In addition, the control unit 10 turns on the first contactor M / C, the third contactor QC / C_A, the fourth contactor QC / C_B, and the first semiconductor switch QC / C_C (second switching unit 42), and turns off the second contactor VS / C_A (third switching unit 43) and the second semiconductor switch VS / C_B (fourth switching unit 44). The circuit mode at this time is called the fourth mode. Thereby, a 400V voltage is supplied from the charging terminals 131P and 131N to the storage battery 2, and a 400V voltage is supplied to the coil 32U via the branch circuit 14.

[0092] Here, in order to drive the auxiliary machine 4 with a base voltage of 800V, it is necessary to boost the 400V voltage to the base voltage of the auxiliary machine 4, which is 800V. Therefore, the control unit 10 performs high-frequency on / off of the second low-side switch TL2 and the third low-side switch TL3 in a state where the first semiconductor switch QC / C_C (second switching unit 42) is turned on and the second semiconductor switch VS / C_B (fourth switching unit 44) is turned off, and performs a boosting operation of switching between the Figure 9 on state of the second low-side switch TL2 and the third low-side switch TL3 shown and the Figure 10 off state of the second low-side switch TL2 and the third low-side switch TL3 shown. In addition, the other switches TL1, TH1 to TH3 of the inverter 5 are maintained in the off state.

[0093] Thereby, in the Figure 9 on state of the second low-side switch TL2 and the third low-side switch TL3 shown, the energy stored in the coils 32U, 32V, and 32W is Figure 10 released in the off state of the second low-side switch TL2 and the third low-side switch TL3 shown, and thereby the 400V voltage supplied from the charging terminals 131P and 131N is boosted to 800V and supplied from the inverter 5 to the auxiliary machine 4.

[0094] Figure 11 This is a diagram showing the flow of current during the second voltage charging (800V charging) of an electric vehicle equipped with the energy storage system 1 of the first embodiment.

[0095] When charging with an 800V-class charging device, the storage battery 2 is controlled to be Figure 5The 800V startup state shown. Additionally, the control unit 10 turns on the first contactor M / C, the third contactor QC / C_A, the fourth contactor QC / C_B, and the second contactor VS / C_A (the third switching unit 43), and turns off the second semiconductor switch VS / C_B (the fourth switching unit 44) and the first semiconductor switch QC / C_C (the second switching unit 42). The circuit mode at this time is referred to as the third mode. Thereby, an 800V voltage is supplied from the charging terminals 131P and 131N to the battery 2, and an 800V voltage is supplied to the auxiliary machine 4 via the power supply circuit 11P and the auxiliary machine drive circuit 12P.

[0096] Figure 12 It is a diagram showing the flow of current during the third voltage charging (1200V charging) of the electric vehicle equipped with the energy storage system 1 of the first embodiment.

[0097] When charging using a 1200V-class charging device, the battery 2 is controlled to be Figure 6 The 1200V startup state shown. Additionally, the control unit 10 turns on the first contactor M / C, the third contactor QC / C_A, the fourth contactor QC / C_B, and the first semiconductor switch QC / C_C (the second switching unit 42), and turns off the second contactor VS / C_A (the third switching unit 43) and the second semiconductor switch VS / C_B (the fourth switching unit 44). The circuit mode at this time is referred to as the second mode. Thereby, a 1200V voltage is supplied from the charging terminals 131P and 131N to the battery 2, and a 1200V voltage is supplied to the coil 32U via the branch circuit 14.

[0098] Here, in order to drive the auxiliary machine 4 with a base voltage of 800V, it is necessary to step down the 1200V voltage to the base voltage of the auxiliary machine 4, which is 800V. Therefore, the control unit 10 turns on and off the first semiconductor switch QC / C_C (the second switching unit 42) at a high frequency to perform a step-down operation of switching between the Figure 13 ON state of the first semiconductor switch QC / C_C (the second switching unit 42) shown in Figure 14 and the OFF state of the first semiconductor switch QC / C_C (the second switching unit 42) shown in

[0099] Thereby, in the Figure 13 ON state of the first semiconductor switch QC / C_C (the second switching unit 42) shown, the energy stored in the coils 32U, 32V, and 32W is in Figure 14When the first semiconductor switch QC / C_C (second switch unit 42) shown is in the off state, it is released, and thus the 1200V voltage supplied from the charging terminals 131P and 131N is stepped down to 800V and supplied from the inverter 5 to the auxiliary machine 4.

[0100] Figure 15 It is a table summarizing the states of the switches and contactors in each mode of the power storage system 1 of the first embodiment.

[0101] Figure 16 It is a flowchart showing the control flow of the power storage system 1.

[0102] First, it is detected whether the electric vehicle equipped with the power storage system 1 is in the driving mode or the charging mode (step S1). In the charging mode, the charging plug is inserted into the charging terminals 131P and 131N. In the driving mode, for example, the power switch is pressed while the user steps on the brake pedal of the electric vehicle. When it is in the driving mode in step S1, the circuit mode of the power storage system 1 is set to the above-mentioned first mode (step S2).

[0103] On the other hand, when it is in the charging mode in step S1, the control unit 10 starts communication with the charging device (step S3) and obtains the charger specifications of the charging device (step S4). When the upper limit voltage of the charger is 1500V in step S4, the circuit mode of the power storage system 1 is set to the above-mentioned second mode (step S5), when the upper limit voltage is 1000V, the circuit mode of the power storage system 1 is set to the above-mentioned third mode (step S6), and when the upper limit voltage is 500V, the circuit mode of the power storage system 1 is set to the above-mentioned fourth mode (step S7).

[0104] If the mode setting of the power storage system 1 is completed, charging is started (step S8), and if charging is completed (step S9), all the switches and contactors of the power storage system 1 are turned off and the process ends (step S9).

[0105] In this way, according to the power storage system 1 of the first embodiment, whether the external charging device is a system that charges with the first voltage (400V charging), a system that charges with the second voltage (800V charging), or a system that charges with the third voltage (1200V charging), by using the first switch unit 41 (S / C_A, S / C_B, S / C_C, S / C_D, S / C_E, S / C_F, S / C_G, S / C_H) to switch the connection modes of the plurality of power storage units 21, charging can be appropriately performed according to the voltage state of the charging device. That is, charging can be performed without passing through a voltage converter during charging, so that deterioration in efficiency caused by the voltage converter can be avoided, and a voltage converter for charging can be dispensed with.

[0106] In addition, since the DC power supply circuit 13P on the positive electrode side connected to the first connection portion 111P on the power transmission path between the inverter 5 and the storage battery 2 has a branch circuit 14 connected to the coil of any one phase of the three-phase motor 3, voltage conversion can be performed using the three-phase motor 3 and the inverter 5. In particular, by including the first semiconductor switch QC / C_C (the second switch portion 42) and the second semiconductor switch VS / C_B (the fourth switch portion 44), even when the voltage state of the charging device and the operating voltage of the auxiliary machine 4 are different, boosting and bucking can be performed using the coil of the three-phase motor 3. As a result, a dedicated voltage converter is not required, and the manufacturing cost can be suppressed.

[0107] [Second Embodiment]

[0108] Next, refer to Figures 17 to 22 The power storage system 1 of the second embodiment will be described. Here, for the structures common to the first embodiment, the description of the first embodiment may sometimes be referred to by using the same reference numerals as those of the first embodiment.

[0109] In the power storage system 1 of the above-described first embodiment, the third contactor QC / C_A, which is the main switch for charging, is connected in series with the first contactor M / C, which is the main switch of the storage battery 2. However, in the power storage system 1 of the second embodiment, as Figure 17 shown, the third contactor QC / C_A is connected in parallel with the first contactor M / C.

[0110] In the power storage system 1 of the second embodiment, during charging at the first voltage (400V) or the third voltage (1200V), the storage battery 2 charged at the first voltage (400V) or the third voltage (1200V) can be separated from the second voltage (800V) boosted by the three-phase motor 3 and the inverter 5 by the first contactor M / C. Therefore, the second contactor VS / C_A of the first embodiment is not provided. Instead, at the middle portion of the branch circuit 14, a fifth contactor QC / C_D for turning the branch circuit 14 on and off is provided on the DC power supply circuit 13P side relative to the first semiconductor switch QC / C_C. In addition, in the power storage system 1 of the second embodiment, the third contactor QC / C_A, the fourth contactor QC / C_B, the fifth contactor QC / C_D, the second voltage sensor V_BAT, and the third voltage sensor V_QC are arranged inside the storage battery 2.

[0111] In the second embodiment, the eight switches (S / C_A, S / C_B, S / C_C, S / C_D, S / C_E, S / C_F, S / C_G, S / C_H) are an example of the first switch unit 41, the first semiconductor switch QC / C_C is an example of the second switch unit 42, and the second semiconductor switch VS / C_B is an example of the fourth switch unit 44, which is the same as the first embodiment. However, it is different from the first embodiment in that the first contactor M / C is an example of the third switch unit 43.

[0112] Refer to Figures 18 to 21 The operation of the power storage system 1 of the second embodiment will be described.

[0113] Figure 18 It is a diagram showing the flow of current when the electric vehicle equipped with the power storage system 1 of the second embodiment is running (800V running).

[0114] As described above, the electric vehicle equipped with the power storage system 1 drives the three-phase motor 3 and the auxiliary machine 4 with a base voltage of 800V, and the storage battery 2 is controlled to be Figure 5 the 800V start state shown. In addition, the control unit 10 turns on the first contactor M / C (the third switch unit 43) and the second semiconductor switch VS / C_B (the fourth switch unit 44), and turns off the third contactor QC / C_A, the fourth contactor QC / C_B, the first semiconductor switch QC / C_C (the second switch unit 42), and the fifth contactor QC / C_D. The circuit mode at this time is called the eleventh mode.

[0115] In this eleventh mode, an 800V voltage is supplied from the storage battery 2 to the three-phase motor 3 via the inverter 5, so the electric vehicle can run. At this time, the auxiliary machine 4 is driven by the 800V voltage supplied from the storage battery 2 via the power supply circuits 11P, 11N and the auxiliary machine drive circuits 12P, 12N.

[0116] Figure 19 It is a diagram showing the flow of current when the first voltage charging (400V charging) of the electric vehicle equipped with the power storage system 1 of the second embodiment is performed.

[0117] When charging with a 400V-class charging device, the storage battery 2 is controlled to be Figure 4The 400V startup state shown. Additionally, the control unit 10 turns on the third contactor QC / C_A, the fourth contactor QC / C_B, the first semiconductor switch QC / C_C (second switch section 42), and the fifth contactor QC / C_D, and turns off the first contactor M / C (third switch section 43) and the second semiconductor switch VS / C_B (fourth switch section 44). The circuit mode at this time is referred to as the fourteenth mode. Thereby, a 400V voltage is supplied from the charging terminals 131P and 131N to the battery 2, and a 400V voltage is supplied to the coil 32U via the branch circuit 14.

[0118] Here, in order to drive the auxiliary machine 4 with a base voltage of 800V, it is necessary to boost the 400V voltage to the base voltage of the auxiliary machine 4, which is 800V. Regarding the boosting operation, as described with reference to the Figure 9 and Figure 10 of the first embodiment, detailed description is omitted. Through the boosting operation, the 400V voltage supplied from the charging terminals 131P and 131N is boosted to 800V and supplied from the inverter 5 to the auxiliary machine 4.

[0119] Figure 20 is a diagram showing the flow of current during the second voltage charging (800V charging) of the electric vehicle equipped with the energy storage system 1 of the second embodiment.

[0120] When charging using an 800V-class charging device, the battery 2 is controlled to be in the Figure 5 800V startup state shown. Additionally, the control unit 10 turns on the first contactor M / C (third switch section 43), the third contactor QC / C_A, and the fourth contactor QC / C_B, and turns off the second semiconductor switch VS / C_B (fourth switch section 44), the first semiconductor switch QC / C_C (second switch section 42), and the fifth contactor QC / C_D. The circuit mode at this time is referred to as the thirteenth mode. Thereby, an 800V voltage is supplied from the charging terminals 131P and 131N to the battery 2, and an 800V voltage is supplied to the auxiliary machine 4 via the power supply circuit 11P and the auxiliary machine drive circuit 12P.

[0121] Figure 21 is a diagram showing the flow of current during the third voltage charging (1200V charging) of the electric vehicle equipped with the energy storage system 1 of the second embodiment.

[0122] When charging using a 1200V-class charging device, the battery 2 is controlled to be in the Figure 6The 1200V startup state shown. In addition, the control unit 10 turns on the third contactor QC / C_A, the fourth contactor QC / C_B, the first semiconductor switch QC / C_C (the second switch unit 42), and the fifth contactor QC / C_D, and turns off the first contactor M / C (the third switch unit 43) and the second semiconductor switch VS / C_B (the fourth switch unit 44). The circuit mode at this time is called the twelfth mode. Thereby, a 1200V voltage is supplied from the charging terminals 131P and 131N to the battery 2, and a 1200V voltage is supplied to the coil 32U via the branch circuit 14.

[0123] Here, in order to drive the auxiliary machine 4 with a base voltage of 800V, it is necessary to step down the 1200V voltage to the base voltage of the auxiliary machine 4, which is 800V. Regarding the step-down operation, as described with reference to the first embodiment Figure 13 and Figure 14 as described, detailed description is omitted. Through the step-down operation, the 1200V voltage supplied from the charging terminals 131P and 131N is stepped down to 800V and supplied from the inverter 5 to the auxiliary machine 4.

[0124] Figure 22 It is a table summarizing the states of switches and contactors in each mode of the power storage system 1 of the second embodiment.

[0125] In this way, in the power storage system 1 of the second embodiment, similar to the first embodiment, whether the external charging device is a system that charges with the first voltage (400V charging), a system that charges with the second voltage (800V charging), or a system that charges with the third voltage (1200V charging), by using the first switch unit 41 (S / C_A, S / C_B, S / C_C, S / C_D, S / C_E, S / C_F, S / C_G, S / C_H) to switch the connection mode of the plurality of power storage units 21, charging can be appropriately performed according to the voltage state of the charging device. That is, during charging, charging can be performed without passing through a voltage converter, so that deterioration in efficiency caused by the voltage converter can be avoided, and a voltage converter for charging can be eliminated.

[0126] In addition, since the DC power supply circuit 13P on the positive electrode side connected to the first connection portion 111P on the power transmission path between the inverter 5 and the storage battery 2 has a branch circuit 14 connected to the coil of any one phase of the three-phase motor 3, voltage conversion can be performed using the three-phase motor 3 and the inverter 5. In particular, by providing the first semiconductor switch QC / C_C (second switch portion 42) and the second semiconductor switch VS / C_B (fourth switch portion 44), even when the voltage state of the charging device and the operating voltage of the auxiliary machine 4 are different, boosting and bucking can be performed using the coil of the three-phase motor 3. Thus, a dedicated voltage converter is not required, and the manufacturing cost can be suppressed.

[0127] As described above, various embodiments have been described with reference to the drawings, but the present invention is of course not limited to this example. Obviously, those skilled in the art can conceive of various modification examples or correction examples within the scope described in the technical solution, and it should be understood that these modification examples and correction examples also of course belong to the technical scope of the present invention. In addition, within the scope not departing from the gist of the invention, the constituent elements in the above-described embodiments can be arbitrarily combined.

[0128] For example, in the above-described embodiment, it has been described that communication is performed between the control unit 10 and the charging device, and any communication method such as CAN communication can be adopted as the communication method.

[0129] At least the following matters are described in this specification. In addition, although the corresponding constituent elements, etc. in the above-described embodiment are shown in parentheses, the present invention is not limited thereto.

[0130] (1) A power storage system (power storage system 1) including:

[0131] A storage battery (storage battery 2) including a switch group (first switch portion 41) and a plurality of power storage portions (power storage portions 21), and the switch group can switch between a first voltage state (400V) capable of charging at a first voltage, a second voltage state (800V) capable of charging at a second voltage higher than the first voltage, and a third voltage state (1200V) capable of charging at a third voltage higher than the second voltage by switching the connection state of the plurality of power storage portions;

[0132] A three-phase motor (three-phase motor 3) having three-phase coils (coils 32U, 32V, 32W) connected to a neutral point (neutral point 31) and driven by power supplied from the storage battery;

[0133] An inverter (inverter 5) connected on the power transmission path (power supply circuits 11P, 11N) between the storage battery and the three-phase motor; and

[0134] A DC power supply circuit (DC power supply circuits 13P and 13N) is connected to a first connection part (first connection parts 111P and 111N) on the power transfer path between the inverter and the storage battery.

[0135] The DC power supply circuit on the positive electrode side has a branch circuit (branch circuit 14), and this branch circuit is connected to any one of the three-phase coils at a second connection part (connection part 34) via a first semiconductor switch (first semiconductor switch QC / C_C).

[0136] For any one of the three-phase coils, a second semiconductor switch (second semiconductor switch VS / C_B) is provided between the second connection part and the inverter.

[0137] According to (1), whether the external charging device is a system that charges with a first voltage, a system that charges with a second voltage, or a system that charges with a third voltage, by using the switch group to switch the connection modes of multiple power storage parts, charging can be appropriately performed according to the voltage state of the charging device. That is, during charging, charging can be performed without passing through a voltage converter, so that the efficiency deterioration caused by the voltage converter can be avoided, and a voltage converter for charging is not required.

[0138] In addition, since the DC power supply circuit on the positive electrode side connected to the first connection part on the power transfer path between the inverter and the storage battery has a branch circuit connected to any one of the coils of the three-phase motor, voltage conversion can be performed using the three-phase motor and the inverter. In particular, by providing the first semiconductor switch and the second semiconductor switch, even when the voltage state of the charging device and the operating voltage of auxiliary machines, etc. are different, boosting and bucking can be performed using the coils of the three-phase motor. Thus, a dedicated voltage converter is not required, and the manufacturing cost can be suppressed.

[0139] (2) The power storage system according to (1), wherein,

[0140] The power storage system further includes:

[0141] An auxiliary machine that can be driven by DC power from the storage battery and an external power supply; and

[0142] An auxiliary machine drive circuit connected to the power transfer path between the inverter and the first connection part for supplying power to the auxiliary machine,

[0143] The auxiliary machine operates at the second voltage.

[0144] According to (2), in the case of charging with the second voltage and during traveling with the second voltage, voltage conversion is not required.

[0145] (3) The power storage system according to (2), wherein,

[0146] The power storage system further includes a control unit (control unit 10), which controls the switch group, the first semiconductor switch, the second semiconductor switch, and the inverter.

[0147] When charging the storage battery with the first voltage, the control unit generates the second voltage by boosting the first voltage through controlling the inverter.

[0148] When charging the storage battery with the third voltage, the control unit generates the second voltage by stepping down the third voltage through controlling the first semiconductor switch, the second semiconductor switch, and the inverter.

[0149] According to (3), whether it is a system charged with the first voltage or a system charged with the third voltage, as long as the auxiliary machine is driven with the second voltage, the amount of voltage conversion during boosting and stepping down can be reduced. Thus, the enlargement of the system can be suppressed.

[0150] (4) The power storage system according to (2) or (3), wherein,

[0151] The auxiliary machine is connected to the storage battery via a switch unit (third switch unit 43).

[0152] According to (4), in the case of charging with the first voltage or the third voltage, the part in the first voltage state and the third voltage state can be separated from the part in the second voltage state through the switch unit.

Claims

1. A power storage system, wherein: The power storage system includes: A storage battery having a switch group and a plurality of power storage units. The switch group can switch between a first voltage state in which the plurality of power storage units can be charged at a first voltage, a second voltage state in which the plurality of power storage units can be charged at a second voltage higher than the first voltage, and a third voltage state in which the plurality of power storage units can be charged at a third voltage higher than the second voltage by switching the connection state of the plurality of power storage units; A three-phase motor having three-phase coils connected at the neutral point and driven by electric power supplied from the storage battery; An inverter connected to the power transmission path between the storage battery and the three-phase motor; and A DC power supply circuit connected to a first connection portion located on the power transmission path between the inverter and the storage battery, The positive electrode side of the DC power supply circuit has a branch circuit, and this branch circuit is connected to any one of the three-phase coils at a second connection portion via a first semiconductor switch, For any one of the three-phase coils, a second semiconductor switch is provided between the second connection portion and the inverter.

2. The power storage system according to claim 1, wherein: The power storage system further includes: An auxiliary machine that can be driven by DC power from the storage battery and an external power source; and An auxiliary machine drive circuit connected to the power transmission path between the inverter and the first connection portion for supplying power to the auxiliary machine, The auxiliary machine operates at the second voltage.

3. The power storage system according to claim 2, wherein: The power storage system further includes a control unit that controls the switch group, the first semiconductor switch, the second semiconductor switch, and the inverter, When charging the storage battery at the first voltage, the control unit boosts the first voltage by controlling the inverter to generate the second voltage, When charging the storage battery at the third voltage, the control unit steps down the third voltage by controlling the first semiconductor switch, the second semiconductor switch, and the inverter to generate the second voltage.

4. The power storage system according to claim 2 or 3, wherein: The auxiliary machine is connected to the storage battery via a switch portion.

Images