Power storage system

Abstract

To provide a power storage system capable of suppressing a manufacturing cost while efficiently performing charging according to a voltage state of charging facilities.SOLUTION: A power storage system 1 includes: a battery 2 that can be charged at 400 V, 800 V, 1200 V; a three-phase motor 3 in which three phase coils are connected at a neutral point 31 and that is driven by power supplied from the battery 2; an inverter 5 connected to power supply circuits 11P and 11N of the battery 2 and the three-phase motor 3; and DC power supply circuits 13P and 13N connected to a power transmission path of the inverter 5 and the battery 2. A DC power supply circuit 13P on a positive electrode side has a branch circuit 14 connected to any one-phase coil of the three-phase coils at a third connecting portion 34. The branch circuit 14 is connected to an auxiliary device drive circuit 12P at a fourth connecting portion 113P via a fourth switch unit 44. The auxiliary device drive circuit 12P is provided with a fifth switch unit 45 between a second connecting portion 112P and the fourth connecting portion 113P.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an electricity storage system. [Background technology]

[0002] In recent years, research and development has been conducted into charging mobility vehicles equipped with secondary batteries that contribute to energy efficiency, in order to ensure that more people have access to affordable, reliable, sustainable, and advanced energy.

[0003] Regarding charging and power supply for mobility vehicles equipped with secondary batteries, there are two types of charging equipment, such as charging stations: 400V class with an upper voltage limit of 500V, and 800V class with an upper voltage limit of 1000V. If a mobility vehicle is only compatible with 400V class charging equipment, it will not be able to take advantage of the rapid charging capabilities of 800V class charging equipment.

[0004] When a mobility device is compatible with 400V and 800V charging facilities, it is generally charged by boosting the voltage to 800V using a voltage converter when charging with 400V charging facilities, or by stepping the voltage down to 400V using a voltage converter when charging with 800V charging facilities. However, charging efficiency decreases when the voltage is passed through a charging voltage converter.

[0005] In contrast, there are also known mobility vehicles that can be charged at both 400V-class charging equipment and 800V-class charging equipment without using a voltage converter for charging by switching the connection method of the battery module (for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 2019-080474 [Patent Document 2] Japanese Patent Application Publication No. 2020-150618 Summary of the Invention [Problem to be solved by the invention]

[0007] Meanwhile, there are two types of accessories used in mobility vehicles: those that are driven by 400V class and those that are driven by 800V class. In mobility vehicles that switch the battery module connection method, voltage conversion is generally performed using a voltage converter for the accessories, such as when driving 400V class accessories while charging with 800V class charging equipment, or when driving 800V class accessories while charging with 400V class charging equipment. However, voltage converters for accessories are expensive and increase manufacturing costs.

[0008] In recent years, higher voltage, lower current charging methods have been proposed to reduce the burden on the power distribution and terminals of mobility charging systems. 1200V-class charging equipment, with a maximum voltage of 1500V, can reduce the burden on the power distribution and terminals of a charging system compared to 400V and 800V-class charging equipment. For example, if the charging equipment has an output of 320kW, theoretically, a 400V-class charging equipment will have a current of 800A, and an 800V-class charging equipment will have a current of 400A. On the other hand, a 1200V-class charging equipment can limit the current to 265A.

[0009] In this way, for mobility vehicles that can be charged using charging equipment with different upper voltage limits by switching the battery module connection method, there is a demand for a power storage system that can operate auxiliary equipment without using expensive auxiliary voltage converters.

[0010] The present invention provides a power storage system that can efficiently charge in accordance with the voltage state of a charging facility while keeping manufacturing costs down. [Means for solving the problem]

[0011] The power storage system of the present invention comprises: a battery including a plurality of power storage units and a group of switches that can switch between a first voltage state in which the battery can be charged at a first voltage, a second voltage state in which the battery can be charged at a second voltage higher than the first voltage, and a third voltage state in which the battery 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 a neutral point and driven by power supplied from the battery; an inverter connected on a power transmission path between the battery and the three-phase motor; a DC power supply circuit connected to a first connection portion located on a power transmission path between the inverter and the battery; an auxiliary device that can be driven by DC power from the battery and an external power source; an accessory drive circuit connected to a second connection part on a power transmission path between the inverter and the first connection part and configured to supply power to the accessory; the DC power supply circuit on the positive electrode side has a branch circuit connected to one of the three-phase coils at a third connection part, the branch circuit is connected to the accessory drive circuit at a fourth connection part via a first changeover switch; The accessory drive circuit is provided with a second changeover switch between the second connection part and the fourth connection part. [Effects of the Invention]

[0012] According to the present invention, it is possible to suppress manufacturing costs while enabling efficient charging according to the voltage state of the charging facility. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram showing a configuration of a power storage system 1 of a first embodiment. [Figure 2] FIG. 2 is a diagram showing the configuration of a battery 2. [Figure 3] FIG. 2 is a diagram showing a configuration of an inverter 5 of the power storage system 1 of FIG. [Figure 4] FIG. 10 is a diagram showing a first voltage state (400 V start-up state) of the battery 2. [Figure 5]10 is a diagram showing a second voltage state (800V start-up state) of the battery 2. FIG. [Figure 6] 10 is a diagram showing a third voltage state (1200V starting state) of the battery 2. FIG. [Figure 7] 2 is a diagram showing a current flow when an electric vehicle equipped with the power storage system 1 of the first embodiment is traveling. FIG. [Figure 8] 3 is a diagram showing a current flow when charging an electric vehicle equipped with the power storage system 1 of the first embodiment at a first voltage (400 V). FIG. [Figure 9] FIG. 2 is a diagram illustrating the voltage boosting operation of the inverter 5. [Figure 10] FIG. 2 is a diagram illustrating the voltage boosting operation of the inverter 5. [Figure 11] FIG. 4 is a diagram showing a current flow when charging the electric vehicle equipped with the power storage system 1 of the first embodiment at a second voltage (800 V). [Figure 12] FIG. 4 is a diagram showing a current flow when charging the electric vehicle equipped with the power storage system 1 of the first embodiment at a third voltage (1200 V). [Figure 13] FIG. 2 is a diagram illustrating the voltage step-down operation of the inverter 5. [Figure 14] FIG. 2 is a diagram illustrating the voltage step-down operation of the inverter 5. [Figure 15] 10 is a table summarizing the states of switches and contactors in each mode of the power storage system 1 of the first embodiment. [Figure 16] FIG. 3 is a flow diagram showing a control flow of the power storage system 1. [Figure 17] FIG. 2 is a diagram showing a configuration of a power storage system 1 according to a second embodiment. [Figure 18] FIG. 10 is a diagram showing a current flow when an electric vehicle equipped with the power storage system 1 of the second embodiment is traveling. [Figure 19] FIG. 10 is a diagram showing a current flow when charging an electric vehicle equipped with the power storage system 1 of the second embodiment at a first voltage (400 V). [Figure 20] FIG. 10 is a diagram showing a current flow when charging at a second voltage (800 V) in an electrically powered vehicle equipped with the power storage system 1 of the second embodiment. [Figure 21]FIG. 10 is a diagram showing a current flow when charging at a third voltage (1200 V) in an electrically powered vehicle equipped with the power storage system 1 of the second embodiment. [Figure 22] 10 is a table summarizing the states of each mode of the power storage system 1 of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, each embodiment of the present invention will be described with reference to the drawings. First, a first embodiment of the present invention will be described with reference to FIGS.

[0015] [First embodiment] The power storage system 1 of the first embodiment shown in Fig. 1 is mounted on an electric vehicle such as an electric car. An electric vehicle mounted with the power storage system 1 is compatible with charging equipment 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, and is not only capable of fast charging the battery 2 at charging voltages of 400V, 800V, and 1200V, but also capable of driving the three-phase motor 3 and auxiliary equipment 4 at a base voltage of 800V. Note that the charging voltages of 400V, 800V, and 1200V are merely examples, and the power storage system 1 is not limited thereto, and may be any type as long as it can be charged by charging equipment with different upper limit voltages.

[0016] Specifically, as shown in Fig. 1, the power storage system 1 includes a battery 2, a three-phase motor 3, an auxiliary machine 4, an inverter 5 (INV), a DC-DC converter 6, power supply circuits 11P and 11N, auxiliary machine drive circuits 12P and 12N, DC power supply circuits 13P and 13N, a branch circuit 14, and a control unit 10. In Fig. 1, reference numeral 7 denotes a drive unit, and reference numeral 8 denotes an auxiliary machine unit.

[0017] As shown in FIGS. 1 and 2, the battery 2 includes six power storage units 21, a first switch unit 41, a main contactor M / C, a precharge contactor P / C, a first resistor R1, a current sensor IS, and a current breaker FUSE.

[0018] The power storage units 21 are battery modules capable of charging and discharging 400V each.

[0019] The main contactor M / C is disposed at the end of the positive electrode side of the battery 2, and functions as a main switch that turns on / off the connection of the battery 2 with the outside (power supply circuit 11P).

[0020] As shown in FIG. 2, 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, and S / C_H). The eight switches are an example of a switch group, and switch the connection state of the six power storage units 21 of the battery 2. In the first voltage state shown in FIG. 4 in which the six power storage units 21 are connected in parallel, the battery 2 can be charged and discharged at 400 V. Hereinafter, this first voltage state in which charging and discharging at 400 V is possible is also referred to as a 400 V start-up state.

[0021] In the second voltage state shown in Fig. 5 in which three power storage units 21 connected in parallel are connected in series, two of them become capable of being charged and discharged at 800V. Hereinafter, this second voltage state in which charging and discharging at 800V is possible will also be referred to as an 800V start-up state. In the third voltage state shown in Fig. 6 in which three power storage units 21 connected in parallel are connected in series, two of them become capable of being charged and discharged at 1200V. Hereinafter, this third voltage state in which charging and discharging at 1200V is possible will also be referred to as a 1200V start-up state.

[0022] Returning to Figure 1, the precharge contactor P / C and first resistor R1 are arranged in series and in parallel with the main contactor M / C. When precharging the smoothing capacitor C1, the precharge contactor P / C is turned on before the main contactor M / C is turned on, thereby protecting the main contactor M / C from excessive inrush current. The precharge contactor P / C is maintained in the off state except when precharging the smoothing capacitor C1.

[0023] The current sensor IS is disposed between the main contactor M / C and the six power storage units 21, and measures the current.

[0024] The current breaker FUSE is disposed at the end of the negative electrode side of the battery 2, and cuts off the connection of the battery 2 to the outside (power supply circuit 11N) in the event of an abnormality. In the power storage system 1 of this embodiment, the current breaker FUSE is configured using a pyro-fuse that can intentionally cut off current in response to an electrical signal, and in the event of an abnormality (such as a vehicle collision or a short circuit in the battery 2), the current breaker FUSE is cut off and all contactors in the battery 2 are turned OFF (open).

[0025] The three-phase motor 3 includes three-phase coils 32U, 32V, and 32W, one end of which is connected at a neutral point 31, and is rotationally driven by power supplied from the battery 2 via the inverter 5. The three-phase motor 3 of this embodiment includes a U-phase terminal 33U, a V-phase terminal 33V, and a W-phase terminal 33W, which are connected to the other ends 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. The other end of any one of the coils 32U, 32V, and 32W is connected to the branch circuit 14 at a third connection 34. In this embodiment, the U-phase coil 32U of the three-phase coils 32U, 32V, and 32W is connected to the branch circuit 14 at the third connection 34, which is located between the U-phase terminal 33U and the inverter 5.

[0026] The inverter 5 converts DC power supplied from the battery 2 into three-phase AC power by switching a plurality of switching elements, thereby rotating and driving the three-phase motor 3. As shown in Fig. 3, the inverter 5 includes a first tributary circuit 51 including 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 tributary circuit 52 including 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, and a third tributary circuit 53 including 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 first tributary circuit 51, the second tributary circuit 52, and the third tributary circuit 53 have their high-side switch side ends connected in parallel to the positive-side power supply circuit 11P, and their low-side switch side ends connected in parallel to the negative-side power supply circuit 11N.

[0027] The first node P1 is connected to the U-phase terminal 33U and is therefore connected to the coil 32U, the second node P2 is connected to the V-phase terminal 33V and is therefore connected to the coil 32V, and the third node P3 is connected to the W-phase terminal 33W and is therefore connected to the coil 32W. The switches TH1, TL1, TH2, TL2, TH3, and TL3 are semiconductor switches, and are formed of, for example, MOSFETs, and are opened and closed by the control unit 10 adjusting the gate voltage.

[0028] A diode that functions as a freewheeling diode is connected in parallel to each of the switches TH1, TL1, TH2, TL2, TH3, and TL3. The freewheeling diodes are provided to prevent damage to the switching elements by returning (regenerating) the current that flows back from the three-phase motor 3 to the battery 2 when the switches TH1, TL1, TH2, TL2, TH3, and TL3 are turned off. That is, the inverter 5 allows current to flow from the three-phase motor 3 to the battery 2 regardless of whether the gate is on or off, and allows current to flow from the battery 2 to the three-phase motor 3 only when the gate is on.

[0029] As will be described in more detail later, when a voltage of 400 V is supplied from the branch circuit 14 to the third connection part 34 during 400 V charging, the energy storage system 1 can cause the three-phase motor 3 to function as part of a step-up circuit by switching the switches TH1, TL1, TH2, TL2, TH3, and TL3. Also, when a voltage of 1200 V is supplied from the power supply circuit 11P to the inverter 5 during 1200 V charging, the three-phase motor 3 can be caused to function as part of a step-down circuit by switching the switches TH1, TL1, TH2, TL2, TH3, and TL3.

[0030] The accessories 4 are high-voltage in-vehicle devices that can be driven by DC power from the battery 2 and an external power source, and include, for example, an electric compressor for an air conditioner and a heater. The accessories 4 are connected to the battery 2 via accessory drive circuits 12P, 12N and power supply circuits 11P, 11N, which will be described later. The accessories 4 are also configured to be connectable to an external power source via accessory drive circuits 12P, 12N, power supply circuits 11P, 11N, and DC power feed circuits 13P, 13N, which will be described later. The accessories 4 are also configured to be connectable to the three-phase motor 3 via a connecting flow path 15 and a branch circuit 14, which will be described later. The accessories 4 of this embodiment operate on a base voltage of 800V.

[0031] The DC-DC converter 6 is connected in parallel to the auxiliary device 4 to the auxiliary device drive circuit 12P, and steps down the DC power from the battery 2 and an external power source to drive low-voltage in-vehicle devices.

[0032] The power supply circuits 11P, 11N are configured as a pair of positive and negative terminals and connect the battery 2 and the inverter 5 (three-phase motor 3). The power supply circuits 11P, 11N are provided with first connectors 111P, 111N as connectors with the DC power supply circuits 13P, 13N, and second connectors 112P, 112N as connectors with the auxiliary equipment drive circuits 12P, 12N are provided closer to the inverter 5 than the first connectors 111P, 111N. The positive-side power supply circuit 11P is also provided with a third switch unit 43 that turns on / off a circuit between the second connector 112P, which is a connector with the auxiliary equipment drive circuit 12P, and the first connector 111P, which is a connector with the DC power supply circuit 13P. The third switch unit 43 is configured with a contactor VS / C_A. The contactor VS / C_A is, for example, an electromagnetic contactor. Therefore, when the third switch section 43 (contactor VS / C_A) is in the ON state, power transmission between the first connection section 111P and the second connection section 112P is permitted, and when the third switch section 43 (contactor VS / C_A) is in the OFF state, power transmission between the first connection section 111P and the second connection section 112P is cut off.

[0033] Furthermore, a first voltage sensor V_PIN, a smoothing capacitor C1, and a second resistor R2 are provided on the inverter 5 side of the power supply circuits 11P, 11N. The first voltage sensor V_PIN, the smoothing capacitor C1, and the second resistor R2 are each provided on a circuit connecting the positive power supply circuit 11P and the negative power supply circuit 11N. The second resistor R2 is provided to discharge the smoothing capacitor C1 when the circuit is interrupted.

[0034] The DC power supply circuits 13P, 13N are each composed of a pair of positive and negative terminals, and are provided at one end with charging terminals 131P, 131N to which an external power source such as a charging facility can be connected, and are connected at the other end to the power supply circuits 11P, 11N via first connectors 111P, 111N. The DC power supply circuits 13P, 13N are provided with contactors QC / C_A and QC / C_B that turn the respective circuits on and off. The contactors QC / C_A and QC / C_B are, for example, electromagnetic contactors. When the contactors QC / C_A and QC / C_B are in the ON state, power supply from the external power source to the power supply circuits 11P, 11N is permitted, and when the contactors QC / C_A and QC / C_B are in the OFF state, power supply from the external power source to the power supply circuits 11P, 11N is cut off.

[0035] Furthermore, in the DC power supply circuits 13P, 13N, a second voltage sensor V_BAT is provided at a position closer to the first connection parts 111P, 111N than the contactors QC / C_A and QC / C_B. Furthermore, a third voltage sensor V_QC is provided at a position closer to the charging terminals 131P, 131N than the contactors QC / C_A and QC / C_B.

[0036] The auxiliary drive circuits 12P, 12N are configured as a pair of positive and negative circuits, with one end connected to the auxiliary 4 and the DC-DC converter 6 in parallel and the other end connected to the power supply circuits 11P, 11N via second connectors 112P, 112N. The positive auxiliary drive circuit 12P is provided with a fifth switch unit 45 that turns the circuit on and off. The fifth switch unit 45 is composed of a contactor VS / C_B. The contactor VS / C_B is, for example, an electromagnetic contactor. Therefore, when the contactor VS / C_B is in an ON state, power is supplied from the positive DC power supply circuit 13P to the auxiliary 4 and the DC-DC converter 6. On the other hand, when the contactor VS / C_B is in an OFF state, power supply from the positive DC power supply circuit 13P to the auxiliary 4 and the DC-DC converter 6 is cut off.

[0037] Branch circuit 14 branches off from positive-side DC power supply circuit 13P at a position closer to first connection 111P than contactor QC / C_A and second voltage sensor V_BAT, and is connected to one of the coils of three-phase motor 3 via third connection 34. Branch circuit 14 is provided with second switch 42 that turns the circuit on and off, and a connecting flow path 15 that branches off from fifth connection 35, which is located closer to third connection 34 than second switch 42, and is connected to accessory drive circuit 12P.

[0038] The second switch unit 42 is composed of a contactor QC / C_C. The contactor QC / C_C is, for example, an electromagnetic contactor. Therefore, when the second switch unit 42 (contactor QC / C_C) is in the ON state, power transmission between the positive DC power supply circuit 13P and the branch circuit 14 is permitted, and when the second switch unit 42 (contactor QC / C_C) is in the OFF state, power transmission between the positive DC power supply circuit 13P and the branch circuit 14 is interrupted.

[0039] The connecting flow path 15 is connected to the positive-side auxiliary equipment drive circuit 12P at a fourth connection part 113P. A fourth switch unit 44 that turns the circuit ON / OFF is provided in the connecting flow path 15. The fourth switch unit 44 is composed of a contactor QC / C_D. The contactor QC / C_D is, for example, an electromagnetic contactor. Therefore, when the fourth switch unit 44 (contactor QC / C_D) is in the ON state, power is supplied from the branch circuit 14 to the auxiliary equipment drive circuit 12P, and when the fourth switch unit 44 (contactor QC / C_D) is in the OFF state, the supply of power from the branch circuit 14 to the auxiliary equipment drive circuit 12P is cut off.

[0040] In addition, the connecting flow path 15 is connected between the fourth switch unit (contactor QC / C_D) and the fourth connection unit 113P to an end of a smoothing capacitor C2, one end of which is connected to the negative power supply circuit 11N.

[0041] 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 controls the first to fifth switch units 41 to 45, ON / OFF control (including PWM control) of each contactor, control of the DC-DC converter 6, and control of the inverter 5.

[0042] Next, the operation of the power storage system 1 will be described with reference to FIGS.

[0043] FIG. 7 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 (running at 800V).

[0044] As described above, the electric vehicle equipped with the power storage system 1 drives the three-phase motor 3 and the accessories 4 with a base voltage of 800V, and when traveling, the battery 2 is controlled to the 800V start state shown in Fig. 5. In addition, the control unit 10 turns on the main contactor M / C, the third switch unit 43 (contactor VS / C_A), and the fifth switch unit 45 (contactor VS / C_B), and turns off the contactor QC / C_A, the contactor QC / C_B, the second switch unit 42 (contactor QC / C_C), and the fourth switch unit 44 (contactor QC / C_D). This circuit mode is referred to as a first mode.

[0045] In this first mode, a voltage of 800 V is supplied from the battery 2 to the three-phase motor 3 via the inverter 5, enabling the electric vehicle to run. At this time, the accessories 4 are driven by a voltage of 800 V supplied from the battery 2 via the power supply circuits 11P, 11N and the accessory drive circuits 12P, 12N.

[0046] FIG. 8 is a diagram showing a current flow during first voltage charging (400V charging) of an electrically powered vehicle equipped with the power storage system 1 of the first embodiment.

[0047] When charging with a 400V-class charging facility, the battery 2 is controlled to the 400V start-up state shown in FIG. 4. The control unit 10 turns on the main contactor M / C, the contactors QC / C_A and QC / C_B, the second switch unit 42 (contactor QC / C_C), and the fifth switch unit 45 (contactor VS / C_B), and turns off the third switch unit 43 (contactor VS / C_A) and the fourth switch unit 44 (contactor QC / C_D). This circuit mode is referred to as a fourth mode. As a result, a voltage of 400V is supplied to the battery 2 from the charging terminals 131P and 131N via the DC power supply circuit 13P and the power supply circuit 11P, and a voltage of 400V is supplied to the coil 32U via the DC power supply circuit 13P and the branch circuit 14.

[0048] Here, in order to drive the auxiliary device 4, which has a base voltage of 800V, it is necessary to boost the voltage of 400V to 800V, which is the base voltage of the auxiliary device 4. Therefore, the control unit 10 performs a boost operation by switching the second low-side switch TL2 and the third low-side switch TL3 at high frequency to switch between the ON state of the second low-side switch TL2 and the third low-side switch TL3 shown in Fig. 9 and the OFF state of the second low-side switch TL2 and the third low-side switch TL3 shown in Fig. 10. Note that the other switches TL1 and TH1 to TH3 of the inverter 5 are maintained in the OFF state.

[0049] As a result, the energy stored in coils 32U, 32V, and 32W when the second low-side switch TL2 and the third low-side switch TL3 shown in Figure 9 are in the ON state is released when the second low-side switch TL2 and the third low-side switch TL3 shown in Figure 10 are in the OFF state, and the voltage of 400V supplied from the charging terminals 131P and 131N is boosted to 800V and supplied from the inverter 5 to the auxiliary equipment 4 via the power supply circuit 11P and the auxiliary equipment drive circuit 12P.

[0050] FIG. 11 is a diagram showing the current flow during second voltage charging (800V charging) of the electric vehicle equipped with the power storage system 1 of the first embodiment.

[0051] When charging with an 800V-class charging facility, the battery 2 is controlled to the 800V start-up state shown in FIG. 5 . The control unit 10 turns on the main contactor M / C, the contactors QC / C_A and QC / C_B, the third switch unit 43 (contactor VS / C_A), and the fifth switch unit 45 (contactor VS / C_B), and turns off the second switch unit 42 (contactor QC / C_C) and the fourth switch unit 44 (contactor QC / C_D). This circuit mode is referred to as a third mode. As a result, a voltage of 800V is supplied to the battery 2 from the charging terminals 131P and 131N via the DC power supply circuit 13P and the power supply circuit 11P, and a voltage of 800V is supplied to the auxiliary equipment 4 via the DC power supply circuit 13P, the power supply circuit 11P, and the auxiliary equipment drive circuit 12P.

[0052] FIG. 12 is a diagram showing the current flow during third voltage charging (1200 V charging) of the electrically powered vehicle equipped with the power storage system 1 of the first embodiment.

[0053] When charging with a 1200V-class charging facility, the battery 2 is controlled to the 1200V start-up state shown in FIG. 6. The control unit 10 turns on the main contactor M / C, the contactors QC / C_A, QC / C_B, the third switch unit 43 (contactor VS / C_A), and the fourth switch unit 44 (contactor QC / C_D), and turns off the second switch unit 42 (contactor QC / C_C) and the fifth switch unit 45 (contactor VS / C_B). This circuit mode is referred to as the second mode. As a result, a voltage of 1200V is supplied to the battery 2 from the charging terminals 131P and 131N via the DC power supply circuit 13P and the power supply circuit 11P, and a voltage of 1200V is supplied to the inverter 5 via the DC power supply circuit 13P and the power supply circuit 11P.

[0054] Here, in order to drive the auxiliary device 4, which has a base voltage of 800V, it is necessary to step down the voltage of 1200V to 800V, which is the base voltage of the auxiliary device 4. Therefore, the control unit 10 performs high-frequency switching of the second high-side switch TH2 and the third high-side switch TH3 to perform a step-down operation that switches between the ON state of the second high-side switch TH2 and the third high-side switch TH3 shown in Fig. 13 and the OFF state of the second high-side switch TH2 and the third high-side switch TH3 shown in Fig. 14. Note that the other switches TH1, and TL1 to TL3 of the inverter 5 are maintained in the OFF state.

[0055] As a result, the energy stored in coils 32U, 32V, and 32W when the second high-side switch TH2 and the third high-side switch TH3 shown in Figure 13 are in the ON state is released when the second high-side switch TH2 and the third high-side switch TH3 shown in Figure 14 are in the OFF state, and the voltage of 1200V supplied from the charging terminals 131P and 131N is reduced to 800V and supplied from the three-phase motor 3 to the auxiliary equipment 4 via the branch circuit 14, the connecting flow path 15, and the auxiliary equipment drive circuit 12P.

[0056] FIG. 15 is a table summarizing the states of the switches and contactors in each mode of the power storage system 1 of the first embodiment.

[0057] FIG. 16 is a flow diagram showing a control flow of the power storage system 1. First, it is detected whether the electric vehicle equipped with the power storage system 1 is in a driving mode or a charging mode (step S1). In the driving mode, for example, the user presses the power switch while stepping on the brake pedal of the electric vehicle. If the driving mode is determined in step S1, the circuit mode of the power storage system 1 is set to the first mode described above (step S2).

[0058] On the other hand, if the charging mode is selected in step S1, when the control unit 10 detects that a charging plug has been inserted into the charging terminals 131P, 131N (step S3), the control unit 10 starts communication with the charging facility (step S4) and acquires the charger specifications of the charging facility (step S5). If the upper limit voltage of the charger is 1500V in step S5, the circuit mode of the power storage system 1 is set to the second mode described above (step S6), if the upper limit voltage is 1000V, the circuit mode of the power storage system 1 is set to the third mode described above (step S7), and if the upper limit voltage is 500V, the circuit mode of the power storage system 1 is set to the fourth mode described above (step S8).

[0059] Once the mode setting of the power storage system 1 is complete, charging is started (step S9), and once charging is completed (step S10), all switches and contactors of the power storage system 1 are turned OFF to end the process (step S11).

[0060] As described above, according to the power storage system 1 of the first embodiment, whether the external charging equipment is a system that charges at a first voltage (400 V charging), a system that charges at a second voltage (800 V charging), or a system that charges at a third voltage (1200 V charging), by switching the connection configuration of the multiple power storage units 21 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), it is possible to charge appropriately according to the voltage state of the charging equipment. In other words, since charging can be performed without going through a voltage converter, it is possible to avoid efficiency degradation due to a voltage converter and to make a voltage converter for charging unnecessary.

[0061] Furthermore, the positive-side DC power supply circuit 13P connected to the first connection part 111P located on the power transmission path between the inverter 5 and the battery 2 has a branch circuit 14 connected to the coil of one of the phases of the three-phase motor 3, so voltage conversion can be performed using the three-phase motor 3 and the inverter 5. In particular, by providing the fourth switch unit 44 (contactor QC / C_D) and the fifth switch unit 45 (contactor VS / C_B), it is possible to not only step up but also step down the voltage using the coil of the three-phase motor 3, even if the voltage state of the charging equipment and the operating voltage of the auxiliary equipment 4 differ. This eliminates the need for a dedicated voltage converter, and reduces manufacturing costs.

[0062] [Second embodiment] Next, a power storage system 1 according to a second embodiment will be described with reference to Fig. 17 to Fig. 22. However, for configurations common to the first embodiment, the same reference numerals as in the first embodiment are used, and the description of the first embodiment may be used.

[0063] In the storage system 1 of the first embodiment described above, when the contactor QC / C_A, which is the main switch for charging, and the main contactor M / C, which is the main switch for the battery 2, are viewed with the battery 2 as the reference, the contactor QC / C_A is connected in series to the main contactor M / C, but in the storage system 1 of the second embodiment, as shown in FIG. 17, the contactor QC / C_A is connected in parallel to the main contactor M / C.

[0064] In the power storage system 1 of the second embodiment, when charging the first voltage (400 V) or the third voltage (1200 V), the main contactor M / C can distinguish between the first voltage (400 V) or the third voltage (1200 V) that is the charging voltage of the battery 2 and the second voltage (800 V) that is boosted by the three-phase motor 3 and the inverter 5, and therefore the contactor VS / C_A of the first embodiment is not provided. Furthermore, in the power storage system 1 of the second embodiment, the contactor QC / C_A, the contactor QC / C_B, the second switch unit 42 (contactor QC / C_C), the second voltage sensor V_BAT, and the third voltage sensor V_QC are arranged in the battery 2.

[0065] 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 a first switch section 41, the contactor QC / C_C is an example of a second switch section 42, the contactor QC / C_D is an example of a fourth switch section 44, and the contactor VS / C_B is an example of a fifth switch section 45, which is similar to the first embodiment, but differs from the first embodiment in that the main contactor M / C is an example of a third switch section 43.

[0066] The operation of the power storage system 1 of the second embodiment will be described with reference to FIGS.

[0067] FIG. 18 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 (running at 800V).

[0068] As described above, the electric vehicle equipped with the power storage system 1 drives the three-phase motor 3 and the accessories 4 with a base voltage of 800V, and when traveling, the battery 2 is controlled to the 800V start state shown in Fig. 5. Furthermore, the control unit 10 turns on the third switch unit 43 (main contactor M / C) and the fifth switch unit 45 (contactor VS / C_B), and turns off the contactor QC / C_A, the contactor QC / C_B, the second switch unit 42 (contactor QC / C_C), and the fourth switch unit 44 (contactor QC / C_D). This circuit mode is referred to as an eleventh mode.

[0069] In this 11th mode, a voltage of 800 V is supplied from the battery 2 to the three-phase motor 3 via the inverter 5, enabling the electric vehicle to run. At this time, the accessories 4 are driven by a voltage of 800 V supplied from the battery 2 via the power supply circuits 11P, 11N and the accessory drive circuits 12P, 12N.

[0070] FIG. 19 is a diagram showing the current flow during first voltage charging (400V charging) of an electrically powered vehicle equipped with the power storage system 1 of the second embodiment.

[0071] When charging with a 400V-class charging facility, the battery 2 is controlled to the 400V start-up state shown in FIG. 4. The control unit 10 also turns on the contactors QC / C_A, QC / C_B, the second switch unit 42 (contactor QC / C_C), and the fifth switch unit 45 (contactor VS / C_B), and turns off the third switch unit 43 (main contactor M / C) and the fourth switch unit 44 (contactor QC / C_D). This circuit mode is referred to as a 14th mode. As a result, a voltage of 400V is supplied to the battery 2 from the charging terminals 131P and 131N via the DC power supply circuit 13P and the power supply circuit 11P, and a voltage of 400V is supplied to the coil 32U via the DC power supply circuit 13P and the branch circuit 14.

[0072] Here, in order to drive the auxiliary device 4, which has a base voltage of 800V, it is necessary to boost the voltage of 400V to 800V, which is the base voltage of the auxiliary device 4. The boost operation is as explained using Figures 9 and 10 in the first embodiment, and a detailed explanation will be omitted. By the boost operation, the voltage of 400V supplied from the charging terminals 131P, 131N is boosted to 800V and supplied to the auxiliary device 4 from the inverter 5 via the power supply circuit 11P and the auxiliary device drive circuit 12P.

[0073] FIG. 20 is a diagram showing the current flow during second voltage charging (800V charging) of an electrically powered vehicle equipped with the power storage system 1 of the second embodiment.

[0074] When charging with an 800V-class charging facility, the battery 2 is controlled to the 800V start-up state shown in FIG. 5. The control unit 10 also turns on the third switch unit 43 (main contactor M / C), contactor QC / C_A, contactor QC / C_B, and fifth switch unit 45 (contactor VS / C_B), and turns off the second switch unit 42 (contactor QC / C_C) and fourth switch unit 44 (contactor QC / C_D). This circuit mode is referred to as a thirteenth mode. As a result, a voltage of 800V is supplied to the battery 2 from the charging terminals 131P and 131N via the DC power supply circuit 13P and the power supply circuit 11P, and a voltage of 800V is also supplied to the auxiliary equipment 4 via the DC power supply circuit 13P, the power supply circuit 11P, and the auxiliary equipment drive circuit 12P.

[0075] FIG. 21 is a diagram showing the current flow during third voltage charging (1200V charging) of an electrically powered vehicle equipped with the power storage system 1 of the second embodiment.

[0076] When charging with a 1200V-class charging facility, the battery 2 is controlled to the 1200V start-up state shown in FIG. 6. The control unit 10 turns on the contactors QC / C_A, QC / C_B, the third switch unit 43 (main contactor M / C), and the fourth switch unit 44 (contactor QC / C_D), and turns off the second switch unit 42 (contactor QC / C_C) and the fifth switch unit 45 (contactor VS / C_B). This circuit mode is referred to as a 12th mode. As a result, a voltage of 1200V is supplied to the battery 2 from the charging terminals 131P and 131N via the DC power supply circuit 13P and the power supply circuit 11P, and a voltage of 1200V is supplied to the inverter 5 via the DC power supply circuit 13P and the power supply circuit 11P.

[0077] Here, in order to drive the auxiliary equipment 4, which has a base voltage of 800 V, it is necessary to step down the voltage of 1200 V to 800 V, which is the base voltage of the auxiliary equipment 4. The step-down operation is as explained using Figures 13 and 14 in the first embodiment, and a detailed explanation will be omitted. By the step-down operation, the voltage of 1200 V supplied from the charging terminals 131P, 131N is stepped down to 800 V and supplied to the auxiliary equipment 4 from the three-phase motor 3 via the branch circuit 14, the connecting flow path 15, and the auxiliary equipment drive circuit 12P.

[0078] FIG. 22 is a table summarizing the states of the switches and contactors in each mode of the power storage system 1 of the second embodiment.

[0079] As described above, in the power storage system 1 of the second embodiment, similarly to the first embodiment, whether the external charging equipment is a system that charges at a first voltage (400 V charging), a system that charges at a second voltage (800 V charging), or a system that charges at a third voltage (1200 V charging), by switching the connection configuration of the plurality of power storage units 21 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), it is possible to charge appropriately according to the voltage state of the charging equipment. In other words, since charging can be performed without going through a voltage converter, it is possible to avoid efficiency degradation due to a voltage converter and to make a voltage converter for charging unnecessary.

[0080] Furthermore, the positive-side DC power supply circuit 13P connected to the first connection part 111P located on the power transmission path between the inverter 5 and the battery 2 has a branch circuit 14 connected to the coil of one of the phases of the three-phase motor 3, so voltage conversion can be performed using the three-phase motor 3 and the inverter 5. In particular, by providing the fourth switch unit 44 (contactor QC / C_D) and the fifth switch unit 45 (contactor VS / C_B), it is possible to not only step up but also step down the voltage using the coil of the three-phase motor 3, even if the voltage state of the charging equipment and the operating voltage of the auxiliary equipment 4 differ. This eliminates the need for a dedicated voltage converter, and reduces manufacturing costs.

[0081] Although various embodiments have been described above with reference to the drawings, it goes without saying that the present invention is not limited to such examples. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that these also naturally fall within the technical scope of the present invention. Furthermore, the components of the above-described embodiments may be combined in any manner without departing from the spirit of the invention.

[0082] For example, in the above embodiment, the control unit 10 communicates with the charging facility, but any communication method such as CAN communication can be adopted.

[0083] This specification describes at least the following items. Note that the components in parentheses correspond to those in the above-described embodiment, but are not limited to these.

[0084] (1) A battery (battery 2) including a plurality of power storage units (power storage units 21) and a group of switches (first switch unit 41) that can switch between a first voltage state in which charging is possible at a first voltage (400 V), a second voltage state in which charging is possible at a second voltage (800 V) higher than the first voltage, and a third voltage state in which charging is possible at a third voltage (1200 V) higher than the second voltage by switching the connection state of the plurality of power storage units; a three-phase motor (three-phase motor 3) in which three-phase coils (coils 32U, 32V, 32W) are connected at a neutral point (neutral point 31) and driven by power supplied from the battery; an inverter (inverter 5) connected on a power transmission path (power supply circuits 11P, 11N) between the battery and the three-phase motor; DC power supply circuits (DC power supply circuits 13P, 13N) connected to first connection parts (first connection parts 111P, 111N) located on a power transmission path between the inverter and the battery; an auxiliary device (auxiliary device 4) that can be driven by DC power from the battery and an external power source; an auxiliary drive circuit (auxiliary drive circuit 12P) connected to a second connection part (second connection part 112P) on a power transmission path between the inverter and the first connection part, and supplying power to the auxiliary; the DC power supply circuit on the positive electrode side has a branch circuit (branch circuit 14) connected to one of the three-phase coils at a third connection part (third connection part 34); The branch circuit is connected to the accessory drive circuit at a fourth connection part (fourth connection part 113P) via a first changeover switch (fourth switch part 44), The accessory drive circuit is provided with a second changeover switch (fifth switch unit 45) between the second connection unit (second connection unit 112P) and the fourth connection unit (fourth connection unit 113P). Energy storage system (Energy storage system 1).

[0085] According to (1), whether the external charging equipment is a system that charges at a first voltage, a system that charges at a second voltage, or a system that charges at a third voltage, by switching the connection configuration of the multiple power storage units with the switch group, it is possible to charge appropriately according to the voltage state of the charging equipment. In other words, since charging can be performed without going through a voltage converter, it is possible to avoid efficiency degradation due to a voltage converter and to make a voltage converter for charging unnecessary. Furthermore, the positive-side DC power supply circuit connected to the first connection part located on the power transmission path between the inverter and the battery has a branch circuit connected to the coil of one of the three-phase motor phases, making it possible to convert voltage using the three-phase motor and inverter. In particular, by providing the first and second selector switches, it is possible to not only step up but also step down the voltage using the coil of the three-phase motor, even if the voltage state of the charging equipment and the operating voltage of the auxiliary equipment differ. This eliminates the need for a dedicated voltage converter and reduces manufacturing costs.

[0086] (2) The power storage system according to (1), The auxiliary equipment operates at the second voltage. Energy storage system.

[0087] According to (2), when charging at the second voltage or when driving a three-phase motor at the second voltage, voltage conversion is not required. Whether charging at the first voltage or the third voltage, the auxiliary equipment can be driven at the second voltage, so the amount of voltage conversion required when stepping up and down can be reduced. This prevents the system from becoming larger.

[0088] (3) The power storage system according to (2), a control unit (control unit 10) that controls the switch group, the first changeover switch, the second changeover switch, and the inverter; The control unit When charging the battery with the first voltage, the first changeover switch is set to a cutoff state and the second changeover switch is set to a connect state to control the inverter, thereby boosting the first voltage to generate the second voltage; When charging the battery with the third voltage, the inverter is controlled with the first changeover switch in a connected state and the second changeover switch in a disconnected state to step down the third voltage and generate the second voltage. Energy storage system.

[0089] According to (3), by controlling the inverter, the voltage can be increased or decreased, so other semiconductor switches are not required, and manufacturing costs can be reduced.

[0090] (4) The power storage system according to (3), The branch circuit is provided with a third changeover switch (second switch unit 42) that cuts off power transmission between the positive-side DC power supply circuit and the branch circuit, a fourth changeover switch (third switch unit 43) is provided between the first connection unit (first connection unit 111P) and the second connection unit (second connection unit 112P) in the power transmission path between the inverter and the battery; The control unit When charging the battery with the first voltage, the third changeover switch is in a connected state and the fourth changeover switch is in a disconnected state; When the battery is charged with the third voltage, the third changeover switch is set to a disconnected state and the fourth changeover switch is set to a connected state. Energy storage system.

[0091] According to (4), when charging at the first voltage or the third voltage, the third and fourth switches can be used to distinguish between the first and third voltage states and the second voltage state.

[0092] (5) The power storage system according to (4), The control unit When the battery is charged with the second voltage and when the three-phase motor is driven with the second voltage, the first changeover switch and the third changeover switch are set to a disconnected state, and the second changeover switch and the fourth changeover switch are set to a connected state. Energy storage system.

[0093] According to (5), it is possible to drive the auxiliary equipment at the second voltage, charge the battery at the second voltage, and drive the three-phase motor at the second voltage without supplying power to the branch circuit.

[0094] (6) The power storage system according to (1), One end of the first changeover switch is connected to the branch circuit, and the other end of the first changeover switch is connected to the negative side (power supply circuit 11N) of the power transmission path between the battery and the three-phase motor via a capacitor. Energy storage system.

[0095] According to (6), the power supplied to the auxiliary equipment can be smoothed. [Explanation of symbols]

[0096] 1. Energy storage system 2 Battery 3 Three-phase motor 4 Auxiliary equipment 5 inverters 10 Control Unit 11N Power supply circuit (negative side power transmission path) 11P Power supply circuit (positive side power transmission path) 12P auxiliary drive circuit 13N DC power supply circuit (negative DC power supply circuit) 13P DC power supply circuit (positive side DC power supply circuit) 14 Branch Circuit 21 Power storage unit 31 Neutral point 32U, 32V, 32W coil 34 Third connection part 41 First switch section (switch group) 42 Second switch section (third changeover switch) 43 Third switch section (fourth changeover switch) 44 4th switch section (1st changeover switch) 45 5th switch section (2nd changeover switch) 111P 1st connection part 112P Second connection part 113P 4th connection part

Claims

1. a battery including a plurality of power storage units and a group of switches that can switch between a first voltage state in which the battery can be charged at a first voltage, a second voltage state in which the battery can be charged at a second voltage higher than the first voltage, and a third voltage state in which the battery can be charged at a third voltage higher than the second voltage by switching connection states of the plurality of power storage units; a three-phase motor having three-phase coils connected at a neutral point and driven by power supplied from the battery; an inverter connected on a power transmission path between the battery and the three-phase motor; a DC power supply circuit connected to a first connection portion located on a power transmission path between the inverter and the battery; an auxiliary device that can be driven by DC power from the battery and an external power source; an accessory drive circuit connected to a second connection part on a power transmission path between the inverter and the first connection part and configured to supply power to the accessory; the positive-electrode DC power supply circuit has a branch circuit connected to one of the three-phase coils at a third connection part, the branch circuit is connected to the accessory drive circuit at a fourth connection part via a first changeover switch; The accessory drive circuit is provided with a second changeover switch between the second connection part and the fourth connection part. Energy storage system.

2. The power storage system according to claim 1, The auxiliary equipment operates at the second voltage. Energy storage system.

3. The power storage system according to claim 2, a control unit that controls the switch group, the first changeover switch, the second changeover switch, and the inverter, The control unit When charging the battery with the first voltage, the first changeover switch is set to a cutoff state and the second changeover switch is set to a connect state to control the inverter, thereby boosting the first voltage to generate the second voltage; When charging the battery with the third voltage, the inverter is controlled with the first changeover switch in a connected state and the second changeover switch in a disconnected state, thereby stepping down the third voltage to generate the second voltage. Energy storage system.

4. The power storage system according to claim 3, the branch circuit is provided with a third changeover switch that cuts off power transmission between the DC power supply circuit on the positive electrode side and the branch circuit, a fourth changeover switch is provided in a power transmission path between the inverter and the battery between the first connection part and the second connection part; The control unit When charging the battery with the first voltage, the third changeover switch is in a connected state and the fourth changeover switch is in a disconnected state; When the battery is charged with the third voltage, the third changeover switch is set to a cutoff state and the fourth changeover switch is set to a connect state. Energy storage system.

5. The power storage system according to claim 4, The control unit When the battery is charged with the second voltage and when the three-phase motor is driven with the second voltage, the first changeover switch and the third changeover switch are set to a disconnected state, and the second changeover switch and the fourth changeover switch are set to a connected state. Energy storage system.

6. The power storage system according to claim 1, one end of the first changeover switch is connected to the branch circuit, and the other end of the first changeover switch is connected to a negative electrode of a power transmission path between the battery and the three-phase motor via a capacitor; Energy storage system.

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