Power storage system

Abstract

To provide a power storage system capable of suppressing manufacturing cost while enabling efficiently charging according to a voltage condition of charging equipment.SOLUTION: A power storage system 1 comprises: a battery 2 chargeable at 400 V, 800 V, or 1200 V; a three-phase motor 3 driven by power fed from the battery 2, whose three-phase coils are connected to a neutral point 31; an inverter 5 connected onto power-feeding circuits 11P, 11N of the battery 2 and the three-phase motor 3; and DC power-feeding circuits 13P, 13N connected to power transmission paths of the inverter 5 and the battery 2. The DC power-feeding circuit 13P on a positive electrode side comprises: a branch circuit 14 connected to any one of the three-phase coils at a connection part 34 via a first semiconductor switch QC / C_C. Any one of the three-phase coils is provided with a second semiconductor switch VS / C_B between the connection part 34 and the inverter 5.SELECTED DRAWING: Figure 1

Description

Technical Field

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

Background Art

[0002] In recent years, in order to enable more people to access affordable, reliable, sustainable, and advanced energy, research and development on charging related to mobility equipped with secondary batteries that contribute to energy efficiency has been carried out.

[0003] Regarding charging in mobility equipped with secondary batteries, there are two types of charging facilities such as charging stands: a 400V class with a maximum voltage of 500V and an 800V class with a maximum voltage of 1000V. If the mobility only supports 400V class charging facilities, it cannot enjoy the fast charging performance of 800V class charging facilities.

[0004] When the mobility supports both 400V class and 800V class charging facilities, generally, when charging with a 400V class charging facility, it is boosted to 800V with a voltage converter for charging, or when charging with an 800V class charging facility, it is stepped down to 400V with a voltage converter for charging. However, passing through the voltage converter for charging during charging deteriorates the efficiency.

[0005] On the other hand, there is also known a mobility that can be charged in both 400V class and 800V class charging facilities without using a voltage converter for charging by switching the connection method of battery modules (for example, Patent Documents 1 and 2).

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0007] On the other hand, there are two types of auxiliary machines used in mobility, those driven at 400V and those driven at 800V. In mobility where the connection method of the battery module is switched, when driving a 400V-class auxiliary machine during charging with an 800V-class charging facility, or when driving an 800V-class auxiliary machine during charging with a 400V-class charging facility, generally, voltage conversion is performed using a voltage converter for the auxiliary machine. However, the voltage converter for the auxiliary machine is expensive and the manufacturing cost increases.

[0008] In recent years, a charging method with a higher voltage and lower current has been proposed to reduce the burden on the power distribution section and terminals of the charging system for mobility. In a 1200V-class charging facility 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 facilities. For example, when the output of the charging facility is 320kW, theoretically, in a 400V-class charging facility, a current of 800A flows, and in an 800V-class charging facility, a current of 400A flows. On the other hand, in a 1200V-class charging facility, the current can be suppressed to 265A.

[0009] As described above, in a mobility that can be charged with charging facilities having different upper limit voltages by switching the connection method of the battery module, a power storage system that can operate the auxiliary machine without using an expensive voltage converter for the auxiliary machine is desired.

[0010] The present invention provides a power storage system that can be efficiently charged according to the voltage state of the charging facility while suppressing the manufacturing cost.

Means for Solving the Problems

[0011] A power storage system according to an aspect of the present invention is A battery comprising: a plurality of power storage units; and a switch group capable of switching 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 units. A three-phase motor in which three-phase coils are connected at a neutral point and driven by electric 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. The DC power supply circuit on the positive electrode side has a branch circuit connected to one of the three-phase coils at a second connection portion via a first semiconductor switch. A second semiconductor switch is provided between the second connection portion and the inverter in one of the three-phase coils.

Advantages of the Invention

[0012] According to the present invention, charging can be efficiently performed according to the voltage state of the charging facility while suppressing the manufacturing cost.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

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Mode for Carrying Out the Invention

[0014] Hereinafter, each embodiment of the present invention will be described with reference to the drawings. First, the first embodiment of the present invention will be described with reference to FIGS. 1 to 16.

[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. The electric vehicle equipped with the power storage system 1 is compatible with charging facilities 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 can not only rapidly charge the battery 2 at charging voltages of 400V, 800V, and 1200V, but also drive the three-phase motor 3 and auxiliary machine 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 it may be possible to charge with charging facilities having 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, 11N, auxiliary machine drive circuits 12P, 12N, DC power supply circuits 13P, 13N, a branch circuit 14, and a control unit 10. In FIG. 1, reference numeral 7 is a drive unit, and reference numeral 8 is 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 first contactor M / C, a pre-charge contactor P / C, a first resistor R1, a current sensor IS, and a current breaker FUSE.

[0018] The power storage unit 21 is a battery module capable of charging and discharging at 400V each.

[0019] The first contactor M / C is disposed at the positive end of the battery 2 and functions as a main switch for turning ON / OFF the connection to the outside of the battery 2 (power supply circuit 11P).

[0020] As shown in FIG. 2, the first switch section 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 and switch the connection states of the six power storage sections 21 of the battery 2. In the first voltage state in which the six power storage sections 21 shown in FIG. 4 are connected in parallel, the battery 2 can be charged and discharged at 400V. Hereinafter, this first voltage state in which charging and discharging are possible at 400V is also referred to as the 400V startup state.

[0021] Also, in the second voltage state in which three power storage sections 21 connected in parallel as shown in FIG. 5 are connected in series in two, the battery 2 can be charged and discharged at 800V. Hereinafter, this second voltage state in which charging and discharging are possible at 800V is also referred to as the 800V startup state. Further, in the third voltage state in which two power storage sections 21 connected in parallel as shown in FIG. 6 are connected in series in three, the battery 2 can be charged and discharged at 1200V. Hereinafter, this third voltage state in which charging and discharging are possible at 1200V is also referred to as the 1200V startup state.

[0022] Returning to FIG. 1, the precharge contactor P / C and the first resistor R1 are arranged in series and arranged in parallel with the first contactor M / C. The precharge contactor P / C is turned ON prior to the turning ON of the first contactor M / C when precharging the smoothing capacitor C1, thereby protecting the first contactor M / C from excessive inrush current. The precharge contactor P / C maintains an OFF state except when precharging the smoothing capacitor C1.

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

[0024] The current breaker FUSE is arranged at the end on the negative electrode side of the battery 2 and cuts off the connection with the outside of the battery 2 (the power supply circuit 11N) when an abnormality occurs. In the power storage system 1 of the present embodiment, the current breaker FUSE is configured by a pyro fuse capable of intentionally cutting off the current according to an electrical signal. When an abnormality occurs (such as a vehicle collision or a short circuit in the battery 2), the current breaker FUSE is operated to cut off, and all the contacts in the battery 2 are turned OFF (opened).

[0025] 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 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 three-phase coils 32U, 32V, and 32W is connected to the branch circuit 14 at the connection portion 34. In the present embodiment, the coil 32U among the three-phase coils 32U, 32V, and 32W is connected to the branch circuit 14 at the connection portion 34 located between the U-phase terminal 33U and the inverter 5.

[0026] A fourth switch portion 44 is provided between the connection portion 34 and the inverter 5 in the U-phase coil 32U to which the branch circuit 14 is connected. The fourth switch portion 44 is composed of a second semiconductor switch VS / C_B. The second semiconductor switch VS / C_B turns ON / OFF the circuit between the connection portion 34 and the inverter 5. The second semiconductor switch VS / C_B is composed of, for example, a MOSFET arranged such that the body diode allows the current to flow 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 blocked, and the flow of current from the inverter 5 side to the connection portion 34 side is allowed. Note that the second semiconductor switch VS / C_B may be any semiconductor switch capable of high-frequency switching, and may be composed of a bipolar transistor, an IGBT, or the like instead of the MOSFET.

[0027] The inverter 5 converts the DC power supplied from the battery 2 into three-phase AC power by switching a plurality of switching elements, and rotationally drives the three-phase motor 3. As shown in FIG. 3, the inverter 5 includes a first branch circuit 51 including a first high-side switch TH1, a first low-side switch TL1, and a first node P1 that serially connects the first high-side switch TH1 and the first low-side switch TL1, a second branch circuit 52 including a second high-side switch TH2, a second low-side switch TL2, and a second node P2 that serially connects the second high-side switch TH2 and the second low-side switch TL2, and a third branch circuit 53 including a third high-side switch TH3, a third low-side switch TL3, and a third node P3 that serially connects the third high-side switch TH3 and the third low-side switch TL3. The first branch circuit 51, the second branch circuit 52, and the third branch circuit 53 are connected in parallel to the positive power supply circuit 11P on the high-side switch side end, and are connected in parallel to the negative power supply circuit 11N on the low-side switch side end.

[0028] Then, the first node P1 is connected to the U-phase terminal 33U and thus connected to the coil 32U, the second node P2 is connected to the V-phase terminal 33V and thus connected to the coil 32V, and the third node P3 is connected to the W-phase terminal 33W and thus connected to the coil 32W. Note that the switches TH1, TL1, TH2, TL2, TH3, and TL3 are constituted by, for example, MOSFETs, and are opened and closed by the control unit 10 adjusting the gate voltage.

[0029] Each of the switches TH1, TL1, TH2, TL2, TH3, and TL3 is connected in parallel with a diode that operates as a freewheeling diode. The freewheeling diode is provided to prevent damage to the switching element by returning (regenerating) the current flowing backward from the motor 24 side to the power supply 11 side when the switches TH1, TL1, TH2, TL2, TH3, and TL3 are turned off. That is, the inverter 5 allows the current to flow from the three-phase motor 3 side to the battery 2 side regardless of the ON / OFF of the gate, and allows the current to flow from the battery 2 side to the three-phase motor 3 side only when the gate is ON.

[0030] As will be described in detail later, when a voltage of 400V is supplied from the branch circuit 14 to the connection part 34, the three-phase motor 3 can function as a part of the boost circuit by switching the switches TH1, TL1, TH2, TL2, TH3, and TL3. Further, when a voltage of 1200V is supplied from the branch circuit 14 to the connection part 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 part 42) and the second semiconductor switch VS / C_B (fourth switch part 44) described later and the switches TH1, TL1, TH2, TL2, TH3, and TL3.

[0031] The auxiliary machine 4 is a high-voltage drive 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 an air conditioner and a heater. The auxiliary machine 4 is connected to the battery 2 via the auxiliary machine drive circuits 12P, 12N, the third switch part 43, and the power supply circuits 11P, 11N described later. The auxiliary machine 4 of the present embodiment operates at a base voltage of 800V.

[0032] The DC-DC converter 6 steps down the DC power from the battery 2 and an external power supply to drive a low-voltage drive in-vehicle device.

[0033] The power supply circuits 11P and 11N are configured as a pair of positive and negative, and connect the battery 2 and the inverter 5 (three-phase motor 3). The power supply circuits 11P and 11N are provided with first connection parts 111P and 111N as connection parts to the DC power supply circuits 13P and 13N. On the inverter 5 side of the first connection parts 111P and 111N, second connection parts 112P and 112N are provided as connection parts to the auxiliary machine drive circuits 12P and 12N (auxiliary machine 4). Also, a third switch part 43 for turning the circuit ON / OFF is provided between the connection part 112P to the auxiliary machine drive circuit 12P and the connection part 111P of the DC power supply circuit 13P in the positive electrode side power supply circuit 11P. The third switch part 43 is composed of a second contact VS / C_A. The second contact VS / C_A is, for example, an electromagnetic contactor.

[0034] Also, on the inverter 5 side of the power supply circuits 11P and 11N, a first voltage sensor V_PIN, a smoothing capacitor C1, and a second resistor R2 are provided. The first voltage sensor V_PIN, the smoothing capacitor C1, and the second resistor R2 are respectively provided on the circuit connecting the positive electrode side power supply circuit 11P and the negative electrode side power supply circuit 11N. Note that the second resistor R2 is provided to discharge the smoothing capacitor C1 when the circuit is interrupted.

[0035] The DC power supply circuits 13P and 13N are configured as a pair of positive and negative. At one end, charging terminals 131P and 131N capable of connecting an external power source such as a charging facility are provided. The other end is connected to the power supply circuits 11P and 11N via the first connection parts 111P and 111N. The DC power supply circuits 13P and 13N are provided with a third contactor QC / C_A and a fourth contactor QC / C_B for turning on / off their respective circuits. Also, a second voltage sensor V_BAT is provided at a position on the first connection parts 111P and 111N side of the third contactor QC / C_A and the fourth contactor QC / C_B. Also, a third voltage sensor V_QC is provided at a position on the charging terminals 131P and 131N side of the third contactor QC / C_A and the fourth contactor QC / C_B.

[0036] The branch circuit 14 branches off at a position on the connection part 111P side from the third contactor QC / C_A and the second voltage sensor V_BAT in the DC power supply circuit 13P on the positive electrode side, and is connected to any coil of the three-phase motor 3 via the connection part 34. A second switch part 42 for turning the circuit ON / OFF is provided in the middle part of the branch circuit 14. The second switch part 42 is composed of the first semiconductor switch QC / C_C. The first semiconductor switch QC / C_C is arranged with MOSFETs in series so that the body diodes are in the reverse direction. 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. Note that the first semiconductor switch QC / C_C may be any semiconductor switch capable of high-frequency switching, and may be composed of a bipolar transistor, an IGBT, etc. instead of the MOSFET.

[0037] 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, each contactor, control of the DC-DC converter 6, and control of the inverter 5.

[0038] Next, the operation of the power storage system 1 will be described with reference to FIGS. 7 to 14.

[0039] 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 (800V running).

[0040] As described above, the electric vehicle equipped with the power storage system 1 drives the three-phase motor 3 and the auxiliary machine 4 at a base voltage of 800V, and during driving, the battery 2 is controlled to the 800V startup state shown in FIG. 5. Further, the control unit 10 turns on the first contactor M / C, the second contactor VS / C_A (third switch unit 43), and the second semiconductor switch VS / C_B (fourth switch unit 44), and turns off the third contactor QC / C_A, the fourth contactor QC / C_B, and the first semiconductor switch QC / C_C (second switch unit 42). The circuit mode at this time is referred to as the first mode.

[0041] In this first mode, a voltage of 800V is supplied from the battery 2 to the three-phase motor 3 via the inverter 5, and the electric vehicle can travel. At this time, the auxiliary machine 4 is driven by a voltage of 800V supplied from the battery 2 via the power supply circuits 11P, 11N and the auxiliary machine drive circuits 12P, 12N.

[0042] FIG. 8 is a diagram showing the flow of current during the first voltage charging (400V charging) of the electric vehicle equipped with the power storage system 1 of the first embodiment.

[0043] When charging with a 400V-class charging facility, the battery 2 is controlled to the 400V startup state shown in FIG. 4. Further, 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 switch unit 42), and turns off the second contactor VS / C_A (third switch unit 43) and the second semiconductor switch VS / C_B (fourth switch unit 44). The circuit mode at this time is referred to as the fourth mode. Thereby, a voltage of 400V is supplied from the charging terminals 131P, 131N to the battery 2, and a voltage of 400V is supplied to the coil 32U via the branch circuit 14.

[0044] Here, in order to drive the auxiliary machine 4 with a base voltage of 800V, it is necessary to boost the 400V voltage to 800V, which is the base voltage of the auxiliary machine 4. Therefore, the control unit 10 performs a boosting operation of high-frequency switching the second low-side switches TL2 and TL3 with the first semiconductor switch QC / C_C (second switch unit 42) turned ON and the second semiconductor switch VS / C_B (fourth switch unit 44) turned OFF, and switching between the ON state of the second low-side switches TL2 and TL3 shown in FIG. 9 and the OFF state of the second low-side switches TL2 and TL3 shown in FIG. 10. Note that the other switches TL1, TH1 to TH3 of the inverter 5 maintain the OFF state.

[0045] As a result, when the second low-side switches TL2 and TL3 are in the ON state shown in FIG. 9, the energy stored in the coils 32U, 32V, and 32W is released when the second low-side switches TL2 and TL3 are in the OFF state shown in FIG. 10, so that 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.

[0046] FIG. 11 is a diagram showing the current flow during the second voltage charging (800V charging) of the electric vehicle equipped with the power storage system 1 according to the first embodiment.

[0047] When charging with an 800V-class charging facility, the battery 2 is controlled to the 800V startup state shown in FIG. 5. Also, 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 (third switch unit 43), and turns OFF the second semiconductor switch VS / C_B (fourth switch unit 44) and the first semiconductor switch QC / C_C (second switch 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.

[0048] FIG. 12 is a diagram showing the flow of current during the third voltage charging (1200V charging) of the electric vehicle equipped with the power storage system 1 of the first embodiment.

[0049] When charging with a 1200V-class charging facility, the battery 2 is controlled to the 1200V startup state shown in FIG. 6. Further, 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 switch unit 42), and turns off the second contactor VS / C_A (third switch unit 43) and the second semiconductor switch VS / C_B (fourth switch unit 44). The circuit mode at this time is referred to as the second mode. As a result, 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.

[0050] 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 800V, which is the base voltage of the auxiliary machine 4. Therefore, the control unit 10 performs a step-down operation of high-frequency switching the first semiconductor switch QC / C_C (second switch unit 42) to switch between the ON state of the first semiconductor switch QC / C_C (second switch unit 42) shown in FIG. 13 and the OFF state of the first semiconductor switch QC / C_C (second switch unit 42) shown in FIG. 14. At this time, the second semiconductor switch VS / C_B (fourth switch unit 44) and the switches TL1 to TL3 and TH1 to TH3 of the inverter 5 maintain the OFF state.

[0051] As a result, when the first semiconductor switch QC / C_C (second switch unit 42) is in the ON state shown in FIG. 13, the energy stored in the coils 32U, 32V, and 32W is released when the first semiconductor switch QC / C_C (second switch unit 42) is in the OFF state shown in FIG. 14, so that 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.

[0052] FIG. 15 is a table summarizing the states of switches and contacts in each mode of the power storage system 1 of the first embodiment.

[0053] FIG. 16 is a flowchart showing the 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 the driving mode or the charging mode (step S1). In the charging mode, a charging plug is inserted into the charging terminals 131P and 131N. In the driving mode, for example, the user presses the power switch while stepping on the brake pedal of the electric vehicle. If it is in the driving mode in step S1, the circuit mode of the power storage system 1 is set to the first mode described above (step S2).

[0054] On the other hand, if it is in the charging mode in step S1, the control unit 10 starts communication with the charging facility (step S3) and acquires the charger specifications of the charging facility (step S4). If 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 second mode described above (step S5). 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 S6). 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 S7).

[0055] When the mode setting of the power storage system 1 is completed, charging is started (step S8). When charging is completed (step S9), all the switches and contacts of the power storage system 1 are turned off and the process ends (step S9).

[0056] According to the power storage system 1 of the first embodiment as described above, whether it is a system charged by an external charging facility at the first voltage (400V charging), a system charged at the second voltage (800V charging), or a system charged at the third voltage (1200V charging), by switching the connection form of the plurality of power storage units 21 with 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 appropriately charge according to the voltage state of the charging facility. That is, since it is possible to charge without passing through the voltage converter during charging, it is possible to avoid the efficiency deterioration caused by the voltage converter and eliminate the need for a voltage converter for charging.

[0057] In addition, since the positive 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 one phase coil 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 (the second switch unit 42) and the second semiconductor switch VS / C_B (the fourth switch unit 44), even when the voltage state of the charging facility and the operating voltage of the auxiliary machine 4 are different, it is possible to not only boost but also step down using the coil of the three-phase motor 3. Thereby, a dedicated voltage converter can be eliminated, and the manufacturing cost can be suppressed.

[0058] [Second Embodiment] Next, the power storage system 1 of the second embodiment will be described with reference to FIGS. 17 to 22. However, for the configurations common to the first embodiment, the same reference numerals as those in the first embodiment may be used, and the description of the first embodiment may be incorporated.

[0059] In the power storage system 1 of the first embodiment described above, the third contactor QC / C_A, which is the main switch for charging, was connected in series to the first contactor M / C, which is the main switch of the battery 2. However, in the power storage system 1 of the second embodiment, as shown in FIG. 17, the third contactor QC / C_A is connected in parallel to the first contactor M / C.

[0060] In the power storage system 1 of the second embodiment, during charging at the first voltage (400 V) or the third voltage (1200 V), the battery 2 charged at the first voltage (400 V) or the third voltage (1200 V) and the second voltage (800 V) boosted by the three-phase motor 3 and the inverter 5 can be separated by the first contactor M / C. Therefore, the second contactor VS / C_A of the first embodiment is not provided. Instead, a fifth contactor QC / C_D for turning the branch circuit 14 on and off is provided in the middle of the branch circuit 14 on the DC power supply circuit 13P side of the first semiconductor switch QC / C_C. Further, 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 in the battery 2.

[0061] 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 section 41, the first semiconductor switch QC / C_C is an example of the second switch section 42, and the second semiconductor switch VS / C_B is an example of the fourth switch section 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 section 43.

[0062] The operation of the power storage system 1 of the second embodiment will be described with reference to FIGS. 18 to 21.

[0063] 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 (800 V running).

[0064] As described above, the electric vehicle equipped with the power storage system 1 drives the three-phase motor 3 and the auxiliary machine 4 at a base voltage of 800V, and during driving, the battery 2 is controlled to the 800V startup state shown in FIG. 5. Further, 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 referred to as the 11th mode.

[0065] In this 11th mode, a voltage of 800V is supplied from the battery 2 to the three-phase motor 3 via the inverter 5, and the electric vehicle can run. At this time, the auxiliary machine 4 is driven by a voltage of 800V supplied from the battery 2 via the power supply circuits 11P, 11N and the auxiliary machine drive circuits 12P, 12N.

[0066] FIG. 19 is a diagram showing the current flow during the first voltage charging (400V charging) of the electric vehicle equipped with the power storage system 1 of the second embodiment.

[0067] When charging with a 400V-class charging facility, the battery 2 is controlled to the 400V startup state shown in FIG. 4. Further, 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 referred to as the 14th mode. Thereby, a voltage of 400V is supplied from the charging terminals 131P, 131N to the battery 2, and a voltage of 400V is supplied to the coil 32U via the branch circuit 14.

[0068] Here, in order to drive the auxiliary machine 4 with a base voltage of 800V, it is necessary to boost the 400V voltage to 800V, which is the base voltage of the auxiliary machine 4. The boosting operation is as described with reference to FIGS. 9 and 10 of the first embodiment, and a detailed description thereof will be omitted. By 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.

[0069] FIG. 20 is a diagram showing the flow of current during the second voltage charging (800V charging) of the electric vehicle equipped with the power storage system 1 of the second embodiment.

[0070] When charging with an 800V-class charging facility, the battery 2 is controlled to the 800V startup state shown in FIG. 5. Further, the control unit 10 turns on the first contactor M / C (the third switch unit 43), the third contactor QC / C_A, and the fourth contactor QC / C_B, and turns off the second semiconductor switch VS / C_B (the fourth switch unit 44), 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 referred to as the 13th 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.

[0071] FIG. 21 is a diagram showing the flow of current during the third voltage charging (1200V charging) of the electric vehicle equipped with the power storage system 1 of the second embodiment.

[0072] When charging with a charging facility of 1200V class, the battery 2 is controlled to the 1200V startup state shown in FIG. 6. Further, 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 referred to as the twelfth mode. Thereby, a voltage of 1200V is supplied from the charging terminals 131P and 131N to the battery 2, and a voltage of 1200V is supplied to the coil 32U via the branch circuit 14.

[0073] 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 800V which is the base voltage of the auxiliary machine 4. The step-down operation is as described with reference to FIGS. 13 and 14 of the first embodiment, and a detailed description thereof is omitted. By 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.

[0074] FIG. 22 is a table summarizing the states of switches and contactors in each mode of the power storage system 1 of the second embodiment.

[0075] Thus, also in the power storage system 1 of the second embodiment, similar to the first embodiment, whether the external charging facility 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 switching the connection form of the plurality of power storage units 21 with 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 appropriately charge according to the voltage state of the charging facility. That is, since charging can be performed without passing through a voltage converter during charging, it is possible to avoid deterioration in efficiency due to the voltage converter and eliminate the need for a voltage converter for charging.

[0076] In addition, since the DC power supply circuit 13P on the positive electrode side 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 one phase coil of the three-phase motor 3, the three-phase motor 3 and the inverter 5 can be used for voltage conversion. In particular, by providing the first semiconductor switch QC / C_C (the second switch part 42) and the second semiconductor switch VS / C_B (the fourth switch part 44), even when the voltage state of the charging facility and the operating voltage of the auxiliary machine 4 are different, it is possible to not only step up but also step down using the coil of the three-phase motor 3. As a result, a dedicated voltage converter can be made unnecessary, and the manufacturing cost can be suppressed.

[0077] As described above, various embodiments have been described with reference to the drawings, but it goes without saying that the present invention is not limited to such examples. It is obvious that those skilled in the art can come up with various modification examples or correction examples within the scope described in the claims, and it is naturally understood that they also belong to the technical scope of the present invention. Also, within the scope not departing from the gist of the invention, the components in the above embodiments may be arbitrarily combined.

[0078] For example, in the above embodiment, it has been described that the control unit 10 communicates with the charging facility, but any communication method such as CAN communication can be adopted as the communication method.

[0079] At least the following matters are described in this specification. Although the corresponding components, etc. in the above-described embodiment are shown in parentheses, it is not limited thereto.

[0080] (1) A battery (battery 2) including a plurality of power storage parts (power storage part 21) and a switch group (first switch part 41) capable of switching between a first voltage state (400V) in which charging is possible at a first voltage, a second voltage state (800V) in which charging is possible at a second voltage higher than the first voltage, and a third voltage state (1200V) in which charging is possible at a third voltage higher than the second voltage by switching the connection state of the plurality of power storage parts. 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 electric power supplied from the battery, An inverter (inverter 5) connected on the power transmission path (power supply circuits 11P, 11N) between the battery and the three-phase motor, A DC power supply circuit (DC power supply circuits 13P, 13N) connected to a first connection portion (first connection portions 111P, 111N) located on the power transmission path between the inverter and the battery, The DC power supply circuit on the positive electrode side has a branch circuit (branch circuit 14) connected to any one of the three-phase coils at a second connection portion (connection portion 34) via a first semiconductor switch (first semiconductor switch QC / C_C), A second semiconductor switch (second semiconductor switch VS / C_B) is provided between the second connection portion and the inverter in any one of the three-phase coils. A power storage system (power storage system 1).

[0081] According to (1), even in a system charged by an external charging facility at a first voltage, a second voltage, or a third voltage, by switching the connection forms of a plurality of power storage units with a switch group, charging can be appropriately performed according to the voltage state of the charging facility. That is, since charging can be performed without passing through a voltage converter during charging, deterioration in efficiency due to the voltage converter can be avoided, and a voltage converter for charging can be made unnecessary. In addition, since the DC power supply circuit on the positive electrode side connected to the first connection portion located on the power transmission path between the inverter and the 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 facility and the operating voltage of auxiliary equipment are different, it is possible not only to boost but also to step down using the coils of the three-phase motor. As a result, a dedicated voltage converter can be made unnecessary, and the manufacturing cost can be suppressed.

[0082] (2) The power storage system according to (1), wherein an auxiliary machine that can be driven by the battery and DC power from an external power source, and an auxiliary machine drive circuit that is connected on the power transmission path between the inverter and the first connection part and supplies power to the auxiliary machine. The auxiliary machine operates at the second voltage. Power storage system.

[0083] According to (2), when charging with the second voltage and when traveling with the second voltage, voltage conversion can be made unnecessary.

[0084] (3) The power storage system according to (2), wherein it includes a control unit (control unit 10) that controls the switch group, the first semiconductor switch, the second semiconductor switch, and the inverter, the control unit when charging the battery with the first voltage, generates the second voltage by boosting the first voltage by controlling the inverter, when charging the battery with the third voltage, generates the second voltage by stepping down the third voltage by controlling the first semiconductor switch, the second semiconductor switch, and the inverter. Power storage system.

[0085] According to (3), whether it is a system that charges with the first voltage or a system that charges with the third voltage, the auxiliary machine may be driven with the second voltage, so the amount of voltage conversion when stepping up and stepping down can be reduced. Thereby, an increase in the size of the system can be suppressed.

[0086] (4) The power storage system according to (2) or (3), wherein the auxiliary machine is connected to the battery via a switch part (third switch part 43).

[0087] According to (4), when charging with the first voltage or the third voltage, the switch unit can separate the portions in the first voltage state and the third voltage state from the portion in the second voltage state.

Explanation of Signs

[0088] 1 Power storage system 2 Battery 3 Three-phase motor 5 Inverter 10 Control unit 14 Branch circuit 21 Power storage unit 31 Neutral point 34 Connection part (second connection part) 41 First switch unit (switch group) 43 Third switch unit (switch unit) VS / C_B Second semiconductor switch (second semiconductor switch) QC / C_C First semiconductor switch (first semiconductor switch)

Claims

1. A battery comprising: a plurality of power storage units; and a switch group capable of switching 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 units. A three-phase motor in which three-phase coils are connected at a neutral point and driven by electric 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. The DC power supply circuit on the positive electrode side has a branch circuit connected to one of the three-phase coils at a second connection portion via a first semiconductor switch. A second semiconductor switch is provided between the second connection portion and the inverter in one of the three-phase coils. A power storage system.

2. The power storage system according to Claim 1, further comprising: an auxiliary machine drivable by DC power from the battery and an external power supply; and an auxiliary machine drive circuit connected on a power transmission path between the inverter and the first connection portion and supplying power to the auxiliary machine. The auxiliary machine operates at the second voltage. A power storage system.

3. The power storage system according to Claim 2, further comprising a control unit that controls the switch group, the first semiconductor switch, the second semiconductor switch, and the inverter, wherein: when charging the battery at the first voltage, the control unit controls the inverter to boost the first voltage to generate the second voltage; and when charging the battery at the third voltage, the control unit controls the first semiconductor switch, the second semiconductor switch, and the inverter to step down the third voltage to generate the second voltage. A power storage system.

4. The power storage system according to any one of Claims 2 or 3, wherein the auxiliary machine is connected to the battery via a switch portion. ​ ​ ​ ​ ​ ​ ​

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